AP POLYCET 2025 Question Paper (Available) : Download Solution PDF with Answer Key

The points \( (1,5), (2,3) \) and \( (-2, -11) \) form a:

• (1) triangle
• (2) parallelogram
• (3) square
• (4) They are collinear

If \( 15 \cot A = 8 \), then \( \sin A = \, ? \)

• (1) \( \dfrac{8}{15} \)
• (2) \( \dfrac{15}{17} \)
• (3) \( \dfrac{17}{15} \)
• (4) \( \dfrac{8}{17} \)

Evaluate \( \dfrac{2 \tan 30^\circ}{1 + \tan^2 30^\circ} \)

• (1) \( \sin 60^\circ \)
• (2) \( \tan 60^\circ \)
• (3) \( \sin 30^\circ \)
• (4) \( \cot 60^\circ \)

Evaluate \( (\sec A + \tan A)(1 - \sin A) = \ ? \)

• (1) \( \sin A \)
• (2) \( \cos A \)
• (3) \( \csc A \)
• (4) \( \sec A \)

Which of the following is true?

• (1) \( \sin(A + B) = \sin A + \sin B \)
• (2) The value of \( \sin \theta \) increases as \( \theta \) increases, \( 0^\circ \leq \theta \leq 90^\circ \)
• (3) The value of \( \cos \theta \) increases as \( \theta \) increases, \( 0^\circ \leq \theta \leq 90^\circ \)
• (4) \( \sin \theta = \cos \theta \) for all values of \( \theta \)

The angle formed by the line of sight with the horizontal when it is above the horizontal level is:

• (1) angle of elevation
• (2) angle of depression
• (3) right angle
• (4) none of these

A ladder is leaned against a wall with angle of \(60^\circ\) with the ground and its foot is 6 feet away from the wall. Then the length of the ladder is:

• (1) \(12\) feet
• (2) \(36\) feet
• (3) \(6\) feet
• (4) \(24\) feet

Two cars are seen from the top of a tower of height 75 m with angles of depression \(30^\circ\) and \(45^\circ\). If the cars are on opposite sides of the tower along the same line, the distance between them is:

• (1) \(75(\sqrt{3}+1)\) m
• (2) \(75(\sqrt{3}-1)\) m
• (3) \(75(\sqrt{3}+1)\) m
• (4) \(75(\sqrt{3}-1)\) m

The number of tangents a circle can have from a point outside the circle is:

• (1) one
• (2) two
• (3) three
• (4) four

The angle made by the tangent at any point of the circle with the radius at the point of contact is:

• (1) \( 0^\circ \)
• (2) \( 45^\circ \)
• (3) \( 60^\circ \)
• (4) \( 90^\circ \)

A tangent \( PQ \) at a point \( P \) of a circle of radius 9 cm meets a line through the center \( O \) at a point \( Q \) such that \( OQ = 15 \) cm. The length of \( PQ \) is:

• (1) \( 12 \, cm \)
• (2) \( 13 \, cm \)
• (3) \( 24 \, cm \)
• (4) \( 25 \, cm \)

Area of a sector of a circle with radius 4 cm and angle 30° is (use \( \pi = 3.14 \)):

• (1) \( 4.08 \, cm^2 \)
• (2) \( 4 \, cm^2 \)
• (3) \( 4.18 \, cm^2 \)
• (4) \( 41.8 \, cm^2 \)

Length of an arc of a sector of angle 45° when the radius of the circle is 3 cm, is:

• (1) \( \frac{5\pi}{4} \, cm \)
• (2) \( \frac{3\pi}{4} \, cm \)
• (3) \( \frac{\pi}{4} \, cm \)
• (4) \( \frac{\pi}{2} \, cm \)

Area of minor segment if a chord of a circle of radius 10 cm subtends a right angle at the centre is (use \( \pi = 3.14 \)):

• (1) 28 cm\(^2\)
• (2) 28.5 cm\(^2\)
• (3) 27 cm\(^2\)
• (4) 27.5 cm\(^2\)

A toy is in the form of a cone of radius \( r \) and lateral height \( l \) mounted on a hemisphere of the same radius, and the total height of the toy is \( h \), then the total surface area of the toy is:

• (1) \( \pi r (2r + l) \)
• (2) \( 2\pi r + l \)
• (3) \( \pi r^2 l \)
• (4) \( \pi r^2 h \)

A model is made with two cones each of height 2 cm attached to the two ends of a cylinder. The diameter of the model is 3 cm and its length is 12 cm. Then the volume of the model is (use \( \pi = \frac{22}{7} \)):

• (1) 24 \( cm^3 \)
• (2) 36 \( cm^3 \)
• (3) 72 \( cm^3 \)
• (4) 66 \( cm^3 \)

The mode and mean of a data are 7 and 5 respectively, then median is:

• (1) 12
• (2) \( \frac{17}{3} \)
• (3) 4
• (4) \( \frac{2}{3} \)

If assumed mean of a data is 47.5, \( \sum f_i d_i = 435 \) and \( \sum f_i = 30 \), then mean of that data is:

• (1) 42
• (2) 52
• (3) 62
• (4) 72

The cumulative frequency of a class is the frequency obtained by:

• (1) adding the frequencies of all the classes preceding the given class
• (2) adding the frequencies of all the classes succeeding the given class
• (3) subtracting the frequencies of all the preceding classes from one another
• (4) None of the above

Formula for finding mode for grouped data is:

• (1) \( l + \left[ \frac{f_1 - f_0}{2f_1 - f_0 - f_2} \right] \times h \)
• (2) \( l - \left[ \frac{f_1 - f_0}{2f_1 - f_0 - f_2} \right] \times h \)
• (3) \( l - \left[ \frac{f_1 - f_0}{2f_1 - f_0 - f_2} \right] - h \)
• (4) None of these

Which of the following cannot be a probability?

• (1) \( \frac{2}{3} \)
• (2) 15%
• (3) 0.7
• (4) -1.5

If \( P(E) = \), then:

• (1) \( 1 - P(E) \)
• (2) \( 1 + P(E) \)
• (3) \( P(E) - 1 \)
• (4) None of these

Which of the following has equally likely outcomes?

• (1) Tossing a coin
• (2) Tossing two coins simultaneously
• (3) Rolling two dice
• (4) All of the above

A card is drawn from a set of 52 cards. The probability of getting a queen card is:

• (1) \( \frac{4}{53} \)
• (2) \( \frac{1}{26} \)
• (3) \( \frac{1}{13} \)
• (4) \( \frac{4}{13} \)

Ram and Syam are friends. Probability that both will have same birthday is:

• (1) \( \frac{364}{365} \)
• (2) \( \frac{1}{365} \)
• (3) \( \frac{1}{364} \)
• (4) \( \frac{363}{365} \)

491400 =

• (1) \( 2^3 \times 3^3 \times 5^3 \times 7 \times 13 \)
• (2) \( 2^3 \times 3^3 \times 5^2 \times 7 \times 13 \)
• (3) \( 2^3 \times 3^2 \times 5^2 \times 7 \times 13 \)
• (4) \( 2^2 \times 3^2 \times 5^2 \times 7 \times 13 \)

Which of the following is not irrational?

• (1) \( 5 - \sqrt{3} \)
• (2) \( 7 - \sqrt{4} \)
• (3) \( \sqrt{2} + \sqrt{3} \)
• (4) \( \sqrt{2} - \sqrt{3} \)

Which of the following is true?

• (1) \( HCF(p \times q \times r) \times LCM(p \times q \times r) = p \times q \times r \)
• (2) \( HCF(p \times q \times r) + LCM(p \times q \times r) = p \times q \times r \)
• (3) \( HCF(p \times q \times r) \times LCM(p \times q \times r) \neq p \times q \times r \)
• (4) \( HCF(p \times q \times r) - LCM(p \times q \times r) = p \times q \times r \)

A prime number \( p \) divides \( a^2 \) where \( a \) is a positive integer, then

• (1) \( p \) divides \( a \)
• (2) \( p \) does not divide \( a \)
• (3) \( p \) is equal to \( a \)
• (4) All of these

The zero of linear polynomial \( ax + b \) is:

• (1) \( \frac{a}{b} \)
• (2) \( \frac{-a}{b} \)
• (3) \( \frac{b}{a} \)
• (4) \( \frac{-b}{a} \)

If the graph of \( y = p(x) \) does not intersect the X-axis at all, then the zeroes of \( p(x) \) are:

• (1) are equal
• (2) are unequal
• (3) don't exist
• (4) All of these

The number of zeroes of a polynomial \( y = p(x) \) as shown below is:

• (1) 0
• (2) 1
• (3) 2
• (4) 3

A pair of linear equations \( a_1 x + b_1 y + c_1 = 0 \) and \( a_2 x + b_2 y + c_2 = 0 \) is such that \( \frac{a_1}{a_2} \neq \frac{b_1}{b_2} \), then they are:

• (1) consistent
• (2) inconsistent
• (3) dependent and consistent
• (4) None of these

The lines \( 2x + 3y - 9 = 0 \) and \( 4x + 6y - 18 = 0 \) are:

• (1) intersecting lines
• (2) coinciding lines
• (3) parallel lines
• (4) All of these

If \( x - 4y - 14 = 0 \) and \( 5x - y - 13 = 0 \) will have:

• (1) unique solution
• (2) no solution
• (3) infinite number of solutions
• (4) None of these

The solution of \( x - 2y = 0 \) and \( 3x + 4y - 20 = 0 \) is:

• (1) \( x = 2, y = 4 \)
• (2) \( x = 4, y = 2 \)
• (3) \( x = -2, y = 4 \)
• (4) \( x = 2, y = -4 \)

The product of Karan’s age five years ago and his age after 9 years from now is 32. This is represented by the quadratic equation:

• (1) \( x^2 + 4x + 77 = 0 \)
• (2) \( x^2 - 4x + 77 = 0 \)
• (3) \( x^2 + 4x - 77 = 0 \)
• (4) \( x^2 - 4x - 77 = 0 \)

The roots of the equation \( 6x^2 - x - 2 = 0 \) are

• (1) \( \frac{2}{3}, -\frac{1}{2} \)
• (2) \( -\frac{2}{3}, \frac{1}{2} \)
• (3) \( -\frac{2}{3}, -\frac{1}{2} \)
• (4) \( \frac{2}{3}, \frac{1}{2} \)

The equation \( 3x^2 - 5x + 2 = 0 \) has

• (1) two real and unequal roots
• (2) two real and equal roots
• (3) no real roots
• (4) None of these

Find two numbers whose sum is 27 and product is 182.

• (1) \( 13, 12 \)
• (2) \( 13, 14 \)
• (3) \( 15, 12 \)
• (4) \( 11, 16 \)

Each one of 100 boxes is filled with 50 one-rupee coins on the first day and 25 more coins are added every next day. The Arithmetic Progression (AP) representing this situation is

• (1) \( 100, 50, 25, 10, \dots \)
• (2) \( 50, 25, 25, 25, \dots \)
• (3) \( 50, 75, 100, 125, \dots \)
• (4) \( 50, 25, 75, 100, \dots \)

Common difference of the AP \( 3, 1, -1, -3, \dots \) is

• (1) \( 1 \)
• (2) \( -2 \)
• (3) \( -1 \)
• (4) \( 2 \)

Tenth term of the AP \( 1, -1, -3, -5, \dots \) is

• (1) \( -15 \)
• (2) \( -17 \)
• (3) \( -13 \)
• (4) \( -10 \)

The sum of the first 22 terms of the AP \( 8, 3, -2, \dots \) is

• (1) \( -979 \)
• (2) \( 979 \)
• (3) \( 1028 \)
• (4) \( -1028 \)

\( D \) and \( E \) are the midpoints of sides \( AB \) and \( AC \) of a triangle \( ABC \) respectively and \( BC = 10 \) cm. If \( DE \parallel BC \), then the length of \( DE \) is

• (1) \( 3 \) cm
• (2) \( 5 \) cm
• (3) \( 4 \) cm
• (4) \( 6 \) cm

Which of the following are not similar figures?

• (1) Circles
• (2) Squares
• (3) Isosceles triangles
• (4) Equilateral triangles

If \( \triangle ODC \sim \triangle OBA \) and \( \angle BOC = 125^\circ \), then \( \angle DOC = ? \)

• (1) \( 60^\circ \)
• (2) \( 55^\circ \)
• (3) \( 50^\circ \)
• (4) \( 65^\circ \)

If \( M\left(\frac{p}{3}, 4\right) \) is the midpoint of the line segment joining \( A(-6, 5) \) and \( B(-4, 3) \), then \( p = ? \)

• (1) \( -10 \)
• (2) \( -8 \)
• (3) \( -9 \)
• (4) \( -15 \)

The distance between the points \( (2, 3) \) and \( (4, 1) \) is

• (1) \( 2\sqrt{2} \)
• (2) \( 2 \)
• (3) \( \sqrt{2} \)
• (4) \( 2\sqrt{3} \)

The coordinates of the point \( P(x, y) \) which divides the line segment joining the points \( A(x_1, y_1) \) and \( B(x_2, y_2) \) internally in the ratio \( m_1 : m_2 \) are

• (1) \( \left( \frac{m_1 x_1 + m_2 x_2}{m_1 + m_2}, \frac{m_1 y_1 + m_2 y_2}{m_1 + m_2} \right) \)
• (2) \( \left( \frac{m_1 x_2 + m_2 x_1}{m_1 + m_2}, \frac{m_1 y_2 + m_2 y_1}{m_1 + m_2} \right) \)
• (3) \( \left( \frac{m_1 x_2 - m_2 x_1}{m_1 + m_2}, \frac{m_1 y_2 - m_2 y_1}{m_1 + m_2} \right) \)
• (4) \( \left( \frac{m_1 x_2 - m_2 x_1}{m_1 - m_2}, \frac{m_1 y_2 - m_2 y_1}{m_1 - m_2} \right) \)

A continuous and closed path of an electric current is called an

• (1) electric charge
• (2) electric conduction
• (3) electric potential
• (4) electric circuit

If a net charge \( Q \) flows across any cross-section of a conductor in time \( t \), then the current \( I \) through the cross-section is

• (1) \( I = \frac{Q}{t} \)
• (2) \( I = \frac{t}{Q} \)
• (3) \( I = \frac{t^2}{Q} \)
• (4) \( I = \frac{Q^2}{t} \)

One coulomb is equivalent to the charge contained in nearly

• (1) \( 0.6 \times 10^{18} \) electrons
• (2) \( 1.6 \times 10^{18} \) electrons
• (3) \( 6.25 \times 10^{18} \) electrons
• (4) \( 16 \times 10^{18} \) electrons

Work done to move a unit charge from one point to the other in an electric circuit is called

• (1) electric potential difference
• (2) electric current
• (3) electric resistance
• (4) electric power

SI unit of electrical potential difference is

• (1) watt
• (2) volt
• (3) ampere
• (4) ohm

The device used to measure electric current in a circuit is called:

• (1) wattmeter
• (2) voltmeter
• (3) ammeter
• (4) resistor

In an electric circuit, three resistors \( 5 \, \Omega \), \( 10 \, \Omega \) and \( 15 \, \Omega \) are connected in series across a \( 60 \, V \) battery. Then the current flowing in the circuit is:

• (1) \( 0.5 \, A \)
• (2) \( 2 \, A \)
• (3) \( 90 \, A \)
• (4) \( 30 \, A \)

The heat produced in a \( 4 \, \Omega \) resistor when an electric current of \( 5 \, A \) flows in it for \( 2 \) seconds is

• (1) \( 200 \, J \)
• (2) \( 40 \, J \)
• (3) \( 50 \, J \)
• (4) \( 80 \, J \)

One kilowatt hour is equal to

• (1) \( 36 \times 10^6 \, J \)
• (2) \( 0.36 \times 10^6 \, J \)
• (3) \( 3.6 \times 10^{10} \, J \)
• (4) \( 3.6 \times 10^6 \, J \)

The power of an electric motor that takes \( 5 \, A \) electric current from a \( 220 \, V \) transmission line is:

• (1) \( 215 \, W \)
• (2) \( 44 \, W \)
• (3) \( 225 \, W \)
• (4) \( 1100 \, W \)

The region surrounding a magnet in which the influence of that magnet can be detected is called

• (1) magnetic length
• (2) magnetic dipole
• (3) magnetic field
• (4) magnetic pole strength

If the electric current through a copper wire increases, the magnitude of the magnetic field produced at a given point:

• (1) decreases
• (2) remains the same
• (3) increases
• (4) becomes equal to zero

The magnetic field at all points inside a solenoid carrying electric current:

• (1) is non-uniform
• (2) is uniform
• (3) does not exist
• (4) is always zero

The direction of force on a current carrying conductor in a magnetic field is given by

• (1) Fleming's left-hand rule
• (2) Newton's laws of motion
• (3) Ohm's law
• (4) Joule's law of heating

The magnetic field produced by a current carrying circular loop is strongest at

• (1) the center of the loop
• (2) a point outside the loop
• (3) the outer surface of the loop
• (4) every point inside the loop

In an electric circuit, the device used to prevent damage to the electrical appliances due to overloading is:

• (1) electromagnet
• (2) electric fuse
• (3) battery
• (4) electric cell

Which of the following is not an alloy?

• (1) Constantan
• (2) Manganin
• (3) Nichrome
• (4) Iron

Identify the wrong statement among the following:

• (1) Magnetic field lines are closed curves
• (2) Inside the magnet, the direction of field lines is from north pole to south pole
• (3) The magnetic field is stronger where the magnetic field lines are crowded
• (4) Magnetic field lines do not intersect with each other

SI unit of electrical resistivity is

• (1) \( \Omega \, m \)
• (2) \( \Omega / m \)
• (3) \( m / \Omega \)
• (4) \( \Omega \, m^2 \)

Which of the following is an insulator?

• (1) Copper
• (2) Silver
• (3) Aluminium
• (4) Rubber

The image formed by a plane mirror is always:

• (1) virtual and erect
• (2) virtual and inverted
• (3) real and erect
• (4) real and inverted

The distance between the pole and the principal focus of a spherical mirror is called:

• (1) image distance
• (2) object distance
• (3) focal length
• (4) radius of curvature

A diminished, virtual and erect image is formed by a

• (1) concave mirror
• (2) convex mirror
• (3) plane mirror
• (4) planoconcave mirror

The mirror used by a dentist to see a large image of the teeth of the patients is

• (1) concave mirror
• (2) convex mirror
• (3) plane mirror
• (4) plano-convex mirror

A ray of light travelling in air enters obliquely into water. This light ray

• (1) bends away from the normal
• (2) passes through the normal at the surface of separation
• (3) bends towards the normal
• (4) travels straight without bending

The focal length of a spherical mirror is \( 10 \, cm \). Its radius of curvature is:

• (1) \( 10 \, cm \)
• (2) \( 5 \, cm \)
• (3) \( 20 \, cm \)
• (4) \( 0.2 \, cm \)

An object placed between the principal focus and center of curvature of a convex lens forms an image:

• (1) beyond the center of curvature
• (2) at infinity
• (3) at the principal focus
• (4) between principal focus and center of curvature

The power of a lens is \( 4 \, D \). Its focal length is

• (1) \( 0.25 \, cm \)
• (2) \( 2.5 \, cm \)
• (3) \( 25 \, cm \)
• (4) \( 0.025 \, cm \)

If the height of the image is equal to the height of an object placed near a spherical lens, then the magnification \( m \) is

• (1) less than 1
• (2) greater than 1
• (3) equal to 1
• (4) equal to zero

An object is placed at a distance of \( 30 \, cm \) from a concave lens of focal length \( 20 \, cm \). The image distance is:

• (1) \( 75 \, cm \)
• (2) \( 60 \, cm \)
• (3) \( 12 \, cm \)
• (4) \( 50 \, cm \)

The delicate membrane having enormous number of light sensitive cells is:

• (1) optic nerve
• (2) retina
• (3) pupil
• (4) cornea

The amount of light entering the eye is regulated and controlled by the

• (1) pupil
• (2) optical nerve
• (3) retina
• (4) ciliary muscles

The minimum distance at which the objects can be seen most distinctly without strain is called

• (1) far point of the eye
• (2) near point of the eye
• (3) range of accommodation
• (4) power of accommodation

A person can see distant objects clearly but cannot see nearby objects distinctly. The person is suffering from:

• (1) hypermetropia
• (2) myopia
• (3) presbyopia
• (4) cataract

The defect myopia can be corrected by using a:

• (1) convex lens
• (2) concave lens
• (3) bifocal lens
• (4) plano convex lens

The band of the coloured components of a light beam is called its

• (1) refraction
• (2) dispersion
• (3) scattering
• (4) spectrum

The formation of a rainbow in the sky involves:

• (1) reflection, refraction, scattering
• (2) refraction, dispersion, reflection
• (3) refraction, scattering, dispersion
• (4) dispersion, total internal reflection, scattering

Advance sunrise and delayed sunset are due to

• (1) atmospheric refraction
• (2) atmospheric scattering
• (3) atmospheric dispersion
• (4) atmospheric reflection

The blue colour of clear sky is due to

• (1) dispersion of light
• (2) refraction of light
• (3) scattering of light
• (4) reflection of light

If the speed of light in glass is \( 2 \times 10^8 \, m/s \) and the speed of light in air is \( 3 \times 10^8 \, m/s \), the refractive index of glass with respect to air is:

• (1) 6
• (2) 1
• (3) 1.5
• (4) 5

Why are cooking vessels made up of metals like copper and aluminium?

• (1) Because they are malleable
• (2) Because they are shiny
• (3) Because they are sonorous
• (4) Because they are good conductors of heat

Why are metals like potassium and sodium stored in kerosene oil?

• (1) To prevent oxidation
• (2) To avoid rusting
• (3) To prevent accidental fires due to their vigorous reaction with oxygen
• (4) To preserve their shiny surface

What is the process of forming a thick oxide layer on aluminium called?

• (1) Galvanisation
• (2) Anodising
• (3) Electrolysis
• (4) Oxidation

What happens when zinc is added to a solution of iron (II) sulfate?

• (1) No reaction takes place
• (2) Both metals react with each other to form an alloy
• (3) Iron displaces zinc and forms iron sulfate
• (4) Zinc displaces iron and forms zinc sulfate

What type of bond is formed when a metal transfers electrons to a non-metal?

• (1) Covalent bond
• (2) Metallic bond
• (3) Ionic bond
• (4) Hydrogen bond

What is the name of the process where carbonate ores are converted to oxides by heating in limited air?

• (1) Calcination
• (2) Electrolysis
• (3) Roasting
• (4) Smelting

Which of the following is an ore of mercury?

• (1) Hematite
• (2) Cinnabar
• (3) Galena
• (4) Bauxite

What kind of bond exists in a molecule of nitrogen (\(N_2\))?

• (1) Single bond
• (2) Double bond
• (3) Triple bond
• (4) Ionic bond

What makes graphite a good conductor of electricity?

• (1) Presence of strong covalent bonds
• (2) Free electrons in its layered structure
• (3) Its rigid three-dimensional structure
• (4) Its slippery texture

What property allows carbon to form large molecules by bonding with itself?

• (1) Valency
• (2) Electronegativity
• (3) Catenation
• (4) Ionization

Compounds with the same molecular formula but different structures are called

• (1) isotopes
• (2) homologous compounds
• (3) functional groups
• (4) isomers

Which series contains compounds differing by a \( -CH_2 - \) unit?

• (1) Homologous series
• (2) Isomeric series
• (3) Saturated series
• (4) Ionic series

Which functional group is present in carboxylic acids?

• (1) \( -CHO \)
• (2) \( -COOH \)
• (3) \( -C=O \)
• (4) \( -OH \)

Which substance can oxidize ethanol to ethanoic acid?

• (1) Alkaline potassium permanganate
• (2) Sodium hydroxide
• (3) Dilute hydrochloric acid
• (4) Sodium ethoxide

What is the product formed when magnesium ribbon is burnt in oxygen?

• (1) Magnesium chloride
• (2) Magnesium oxide
• (3) Magnesium carbonate
• (4) Magnesium hydroxide

What is the law of conservation of mass?

• (1) Energy can be created in a reaction
• (2) The number of reactants must always equal the number of products
• (3) Mass and energy are interchangeable during reactions
• (4) Mass can neither be created nor destroyed in a chemical reaction

What is the law of conservation of mass?

• (1) Energy can be created in a reaction
• (2) The number of reactants must always equal the number of products
• (3) Mass and energy are interchangeable during reactions
• (4) Mass can neither be created nor destroyed in a chemical reaction

What is the significance of writing physical states in a chemical equation?

• (1) To provide information about the physical form of substances
• (2) To show the mass of reactants and products
• (3) To balance the equation more accurately
• (4) To indicate the catalyst used in the reaction

What is the product formed when slaked lime reacts with carbon dioxide during whitewashing?

• (1) Calcium hydroxide
• (2) Calcium carbonate
• (3) Calcium oxide
• (4) Calcium chloride

Why does the iron nail become brownish when dipped in copper sulfate solution?

• (1) Copper gets deposited on the nail
• (2) Iron reacts with oxygen
• (3) The nail rusts
• (4) The nail undergoes thermal decomposition

What causes corrosion of iron?

• (1) Exposure to sunlight
• (2) Reaction with oxygen and moisture
• (3) Contact with acids
• (4) Both (2) and (3)

What is the process called when fats and oils are oxidised and their smell and taste change?

• (1) Corrosion
• (2) Rancidity
• (3) Combustion
• (4) Oxidation

If someone in your family is suffering from acidity after overeating, which of the following would you suggest as a remedy?

• (1) Lemon juice
• (2) Vinegar
• (3) Baking soda solution
• (4) Saltwater

Which of the following can be used as olfactory indicators?

• (1) Vanilla essence, turmeric and clove oil
• (2) Red cabbage, vanilla essence and onion
• (3) Turmeric, onion and litmus
• (4) Vanilla essence, onion and clove oil

Phenolphthalein is used as an indicator in the reaction between

• (1) acid and base
• (2) acid and metal
• (3) base and metal oxide
• (4) acid and non-metallic oxide

Which of the following is a synthetic indicator?

• (1) Turmeric
• (2) Methyl orange
• (3) Litmus solution
• (4) Red cabbage extract

Why do acidic solutions conduct electricity?

• (1) Due to the presence of water molecules
• (2) Due to the presence of free electrons
• (3) Due to the presence of ions in the solution
• (4) Because acids are solid conductors

Tooth decay begins when the pH of the mouth drops below:

• (1) 6.5
• (2) 5.5
• (3) 4.5
• (4) 7.0

What chemical is responsible for the pain caused by a bee sting?

• (1) Methanoic acid
• (2) Hydrochloric acid
• (3) Acetic acid
• (4) Sulphuric acid

What is the chemical formula of Plaster of Paris?

• (1) \(CaSO_4 \cdot 2H_2O\)
• (2) \(CaSO_4 \cdot \frac{1}{2}H_2O\)
• (3) \(CaCO_3\)
• (4) \(CaOCl_2\)

Which property of metals describes their shiny surface?

• (1) Malleability
• (2) Ductility
• (3) Metallic luster
• (4) Conductivity