CBSE Class X – Science Chemistry Exam (Full Syllabus)

This test is designed based on NCERT Syllabus for Class 10 Topics of Science – Chemistry

Each time random 25 questions will be displaced from the question bank of 500 + Questions
So we recommend you to retake the quiz till you have mastered all the questions

1 / 25

Identify the reducing agent in the following reactions 4NH₃ + 5O₂ → 4NO + 6H₂O

O₂

NH₃

NO

H₂O

2 / 25

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, the colour of the solution fades and a black precipitate is obtained.Write the chemical name of the black precipitate formed.

hydrogen sulphide

copper sulphide.

hydrogen sulphate

none of these

3 / 25

On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed. Identify the brown gas X evolved.

X is nitrogen dioxide gas (NO<sub>2</sub>) that has evolved as brown, choking fumes

X is copper oxide gas that has evolved as brown, choking fumes

X is oxygen gas that has evolved as brown, choking fumes.

none of these

4 / 25

Which of the following reactions is an endothermic reaction?

Burning of coal.

Decomposition of vegetable matter into compost

Process of respiration.

Decomposition of calcium carbonate to form quick lime and carbon dioxide

5 / 25

Calcium oxide reacts vigorously with water to produce slaked lime. CaO(s) + H₂O(l) → Ca(OH)₂(aq) This reaction can be classified as:

Combination reaction

Exothermic reaction

Endothermic reaction

Oxidation reaction

1 and 3

3 and 4

1, 3 and 4

1 and 2

6 / 25

The chemical formula for methonic acid

H2COH

HOOCH

HCOOH

None

7 / 25

What types of ions are formed when an acid is dissolved in water ?

H+ ions are formed

H<sub>2</sub>0 +

OH- ions

None

8 / 25

How many water molecules are present in plaster of paris

one third

half

4

2

9 / 25

On strong heating, blue coloured copper sulphate crystals turns

purple

red

white

blue

10 / 25

Which of the following statements is true for acids?

Bitter and change red litmus to blue

Sour and change red litmus to blue

Sour and change blue litmus to red.

Bitter and change blue litmus red

11 / 25

The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belongs to the identical group?

A and B

B and D

A and C

D and E

12 / 25

The electronic confgurations of three elements X, Y and Z are: X : 2 Y : 2, 8, 7 Z : 2, 8, 2 Which of the following is true regarding these elements?

X is a metal

Y is a metal

Z is a non-metal

Y is a non-metal and Z is a metal

13 / 25

Which of the following are the characteristics of isotopes of an element?

Isotopes of an element have the same atomic masses.

Isotopes of an element have the same atomic number

Isotopes of an element show the same physical properties.

Isotopes of an element show the same chemical properties.

2 and 4

1 and 3

2 and 3

1 and 4

14 / 25

Why does atomic radius decreases as we move from left to right in a period

due to increase in nuclear charge which tends to pull the electrons closer to the nucleus.

due to decrease in nuclear charge which tends to pull the electrons closer to the nucleus.

due to no change in nuclear charge which tends to pull the electrons closer to the nucleus.

none of these

15 / 25

The number of groups in the Modern Periodic Table

18

14

12

10

16 / 25

A molecule of ammonia (NH₃) has:

Only single bonds

Only double bonds

Only triple bonds

Two double bonds and one single bond

17 / 25

The I.U.P.A.C name of CH₃CH₂CH=CH₂ is?

3-Butene

Prop-1-ene

But-1-ene

Butyne

18 / 25

Ethene is

saturated hydrocarbon

unsaturated hydrocarbon

both 1 & 2

none

19 / 25

The compounds have low melting and boiling points.

covalent compounds

ionic compounds

molecular compounds

both 1 & 2

20 / 25

The molecular formula of Ethanol

C₂H₆OH

C₂H₇OH

C₂H₅OH

C₂HOOH

21 / 25

Which of the subsequent oxide(s) of iron would be obtained on prolonged reaction of iron with steam?

FeO

Fe₂O₃

Fe₃O₄

Fe₂O₃ and Ce₃O₄

22 / 25

Which among the following Declaration is incorrect for magnesium metal?

It burns in oxygen with a dazzling white fame

It reacts with cold water to form magnesium oxide and evolves hydrogen gas.

It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas.

It reacts with steam to form magnesium hydroxide and evolves hydrogen gas.

23 / 25

2 ml each of conc. HCl, HNO₃, and a mixture of conc. HCl and conc. HNO3 in the ratio of 3:1 were taken in test tubes labelled as : A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C. The metal could be:

AI

Au

Cu

Pt

2 and 4

1

2

1 and 3

24 / 25

Why should we not throw small pieces of sodium into a sink in the laboratory? Because of

endothermic reaction

exothermic reaction

oxidation

none of these

25 / 25

Name one metal that exist in liquid state at room temperature.

bromine

mercury

sodium

silver

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CBSE Class X – Science Chemistry Exam (Full Syllabus)

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