Science : Ch 01 – Chemical Reactions and Equations

Science : Ch 01 - Chemical Reactions and Equations

This test is designed based on NCERT Syllabus for Class 10 Topics : Chemical Reactions and Equations

Each time random 15 questions will be displaced
So retake the quiz till you have mastered all the questions

1 / 15

Why are oil and fat containing food items fushed with nitrogen while packing?

to prevent reduction

To prevent rancid

to increase oxidation

none of these

2 / 15

Identify the reducing agent in the following reactions: 2H₂O + 2F₂ → 4HF + O₂

H₂O

F₂

HF

O₂

3 / 15

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.Why does the colour of the solution fades?

due to its reaction with hydrogen sulphide gas and results into the formation of colourless solution of sulphuric acid.

due to its reaction with Copper sulphate gas and results into the formation of colourless solution of sulphuric acid.

Both 1 & 2

all of these

4 / 15

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

5 / 15

Mention whether it is a physical or chemical changes: -Evaporation of petrol

physical

chemical

Both 1 & 2

none of these

6 / 15

Sate the reactions exothermic or endothermic in nature: Dissolution of sodium hydroxide in water

endothermic reaction

both 1 & 3

exothermic reaction

all of these

7 / 15

State the reactions are exothermic or endothermic in nature: Dissolution of ammonium chloride in water

exothermic reaction

endothermic reaction

Both 1 & 2

none of these

8 / 15

In the electrolysis of water, name the gases liberated at cathode

Hydrogen

H₂O

Oxygen

both 1 & 3

9 / 15

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

10 / 15

Which of the following gases can be used for the storage of fresh sample of an oil for a long duration?

Carbon dioxide or oxygen

Nitrogen or oxygen

Carbon dioxide or helium

Helium or nitrogen

11 / 15

When copper turning are added to silver nitrate solution, a blue coloured solution is formed after some time. It is because copper ?

Displaces silver from the solution

Forms a blue colored complex with AgNO₃

Is oxidized to Cu₂₊

Is reduced to Cu₂₊

12 / 15

You are given the solution of lead nitrate. In order to obtain a yellow precipitate you should blend with it a solution of:

potassium nitride

potassium sulphide

potassium iodide

13 / 15

Dilute hydrochloric acid is added to granulated zinc taken in a test tube. The following observations are recorded. Designate the accurate observation:

The surface of metal becomes shiny.

The reaction mixture turns milky.

Odour of a pungent smelling gas is recorded.

A colourless and odourless gas is evolved

14 / 15

Which of the subsequent does show an oxidation reaction

Gain of oxygen

Loss of oxygen

Gain of hydrogen

None of the above

15 / 15

Three beakers labelled as A, B and C, each containing 25 ml of water, were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in the case of beaker C, the temperature of the solution fell. Which one of the following statement(s) is (are) correct?

In beakers A and B, exothermic process has occurred.

In beakers A and B, endothermic process has occurred

In beaker C, exothermic process has occurred

In beaker C, endothermic process has occurred.

1

2

1 and 4

2 and 3

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Science : Ch 01 – Chemical Reactions and Equations

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