Selina solutions for Concise Chemistry [English] Class 9 ICSE chapter 6 - Study of the First Element - Hydrogen [Latest edition]

Compare hydrogen with alkali metals on the basis of:

Ion formation

Compare hydrogen with alkali metals on the basis of:

Reducing power

Compare hydrogen with alkali metals on the basis of:

Reaction with oxygen

Compare hydrogen with alkali metals on the basis of:

Oxide formation 

In what respect does hydrogen differ from:

alkali metals

In what respect does hydrogen differ from:

halogens? 

Give the general group study of hydrogen with reference to

valence electrons

Give the general group study of hydrogen with reference to

burning

Give the general group study of hydrogen with reference to

reducing power 

Compare hydrogen and halogens on the basis of:

physical state

Compare hydrogen and halogens on the basis of:

ion formation

Compare hydrogen and halogens on the basis of:

valency 

Compare hydrogen and halogens on the basis of:

reaction with oxygen 

Which metal is preferred for the preparation of hydrogen?

from water?

Which metal is preferred for the preparation of hydrogen?

from acid? 

Write the reaction of steam with a red hot iron.

Why this reaction is considered a reversible reaction?

Why zinc and aluminium are considered to have a unique nature. Give balanced equations to support your answer.

Write a balanced equation for the following:

Iron reacts with dil. HCl

Write a balanced equation for the following:

Zinc reacts with caustic soda solution

Write a balanced equation for the following:

Lead reacts with potassium hydroxide

Write a balanced equation for the following:

Aluminium reacts with fused sodium hydroxide.

Write the balanced equation and give your observation when the following metal reacts:

Sodium with cold water

Write the balanced equation and give your observation when the following metal reacts:

Calcium with cold water

Write the balanced equation and give your observation when the following metal reacts:

Magnesium with boiling water

Write the balanced equation and give your observation when the following metal reacts:

Magnesium with steam

Under what conditions iron reacts with water.

Give the balanced equation of the reaction.

What is noticed if the products are not allowed to escape?

From the knowledge of activity series, name a metal which shows the following properties

It reacts readily with cold water

From the knowledge of activity series, name a metal which shows the following properties:

It displaces hydrogen from hot water.

From the knowledge of activity series, name a metal which shows the following properties:

It displaces hydrogen from dilute HCl.

From the knowledge of activity series, name a metal which shows the following properties:

It forms a base which is insoluble in water. 

Complete the following word equation:

Sodium hydroxide + zinc → hydrogen + _________

Complete the following word equation:

Calcium + water → calcium hydroxide + _________

Hydrogen can be prepared with the metal zinc by using:

acid

Hydrogen can be prepared with the metal zinc by using: alkali

Hydrogen can be prepared with the metal zinc by using: water

For laboratory preparation of hydrogen, give the following:

materials used

For laboratory preparation of hydrogen, give the following:

method of collection

For laboratory preparation of hydrogen, give the following:

chemical equation

For laboratory preparation of hydrogen, give the following:

fully-labeled diagram 

Name the impurities present in hydrogen prepared in the laboratory.

How can these impurities be removed? 

Hydrogen is manufactured by the 'Bosch Process'.

Give the equation with conditions.

Hydrogen is manufactured by the 'Bosch Process'.

How can you obtain hydrogen from a mixture of hydrogen and carbon monoxide? 

Give an equation to express the reaction between:

Steam and red hot iron

Give an equation to express the reaction between:

Calcium and water 

A small piece of calcium metal is put into a small trough containing water. There is effervescence and white turbidity is formed.

Name the gas formed in the reaction. How would you test the gas?

A small piece of calcium metal is put into a small trough containing water. There is effervescence and white turbidity is formed.

Write an equation for the reaction.

A small piece of calcium metal is put into a small trough containing water. There is effervescence and white turbidity is formed.

What do you observe when a few drops of red litmus solution are added to the turbid solution.

Thin strips of magnesium, copper, and iron are taken.

Write down what happens when these metals are treated as follows:

1. Heated in presence of air
2. Heated with dil.HCl
3. Added to an aqueous solution of zinc sulphate.

Thin strips of magnesium, copper, and iron are taken.

Arrange these metals in descending order of reactivity. 

Choose the correct option:

Hydrogen is evolved by the action of cold dil. HNO₃ on

Choose the correct option:

Which metal absorbs hydrogen?

Choose the correct option:

The composition of the nucleus of deuterium is

Choose the correct option:

Elements which show unique nature in the preparation of hydrogen are:

Give a reason for the following:

Zinc granules are used in the lab preparation of hydrogen.

Give reason for the following:

Purified and dried hydrogen is collected over mercury.

Give reason for the following:

The end of the thistle funnel should be dipped under acid.

Give reason for the following:

Dilute sulphuric acid cannot be replaced by concentrated acid in the preparation of hydrogen.

Where does hydrogen occur in a free state?

How did the name 'hydrogen' originate? 

Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with:

A monovalent metal

Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with:

A divalent metal 

Which metal is preferred for collecting hydrogen from Cold water? Write the balanced equation.

Which metal is preferred for collecting hydrogen from:
Write the balanced equation

Hot water

Which metal is preferred for collecting hydrogen from steam? Write the balanced equation for the case.

Hydrogen may be prepared in the laboratory by the action of a metal on an acid.

Which of the metals copper, zinc, magnesium or sodium would be the most suitable?

Hydrogen may be prepared in the laboratory by the action of a metal on an acid.

Which of the acids dilute sulphuric, concentrated sulphuric, dilute nitric acid and concentrated nitric acid would you choose? Explain why you would not use the acids you reject.

Hydrogen may be prepared in the laboratory by the action of a metal on an acid.

How would you modify your apparatus to collect dry hydrogen? Which drying agent would you employ for this purpose? 

Why are the following metals not used in the lab preparation of hydrogen?

calcium

Why are the following metal not used in the lab. preparation of hydrogen?

iron

Why are the following metals not used in the lab. preparation of hydrogen?

aluminium 

Why are the following metals not used in the lab. preparation of hydrogen?

sodium 

Based on the reactions of water on metals, arrange the following metals in increasing order of reactivity: iron, sodium, magnesium, zinc, calcium

Hydrogen is obtained by displacement from:

1. dilute sulphuric acid
2. dilute hydrochloric acid

Write equations using zinc and iron.
Why does copper not show similar behavior?

Account for the following fact:

Though lead is above hydrogen in the activity series, it does not react with dilute hydrochloric acid or dilutes sulphuric acid.

Give reason for the following:

Potassium and sodium are not used for reaction with dilute hydrochloric acid or dilute sulphuric acid in the laboratory preparation of hydrogen. 

Complete and balance the following reaction.

Na + H₂O →_____________ +___________

Complete and balance the following reaction.

Ca + H₂O →_____________ +___________

Complete and balance the following reaction.

Mg + H₂O →_____________ +___________

Complete and balance the following reaction.

Zn + H₂O →_____________ +___________

Complete and balance the following reaction.

Fe + H₂O →_____________ +___________

Complete and balance the following reaction.

Zn + HCl →_____________ +___________

Complete and balance the following reaction.

Al + H₂SO₄ →_____________ +___________

Complete and balance the following reaction.

Fe + HCl →_____________ +___________

Complete and balance the following reaction.

Zn + NaOH →_____________ +___________

Complete and balance the following reaction.

Al + KOH + H₂O→_____________ +___________ 

Metal in the powdered form reacts very slowly with boiling water, but it decomposes in steam. Name the metal.

Write a balanced equation for the reaction named metal with (i) boiling water (ii) steam.

Under what conditions can hydrogen be made to combine with nitrogen?

Under what conditions can hydrogen be made to combine with chlorine?

Name the products and write the equation for the reaction.

Under what conditions can hydrogen be made to combine with sulphur?

Name the products and write the equation for the reaction.

Under what conditions can hydrogen be made to combine with oxygen?

Name the products and write the equation for the reaction.

When hydrogen is passed over a black solid compound A, the products are a 'colorless liquid' and a 'reddish-brown metal B'.

Substance B is divided into two parts each placed in separate test tubes.

Dilute HCl is added to one part of substance B and dilute HNO₃ to the other.

1. Name the substances A and B.
2. Give two tests for the colourless liquid formed in the experiment.
3. What happens to substance A when it reacts with hydrogen? Give reasons for your answer.
4. Write an equation for the reaction between hydrogen and substance A.
5. Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.

Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.

Is it essential that oxidation and reduction must occur side by side in a chemical reaction? Explain

State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

PbO + CO → Pb + CO₂

State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

Mg + 2HCl → MgCl₂ + H₂

State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

H₂S + Cl₂→ 2HCl + S

State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

Cl₂ + H₂S → 2HCl + S 

State whether the following conversion is oxidation or reduction:

PbO₂ + SO₂→ PbSO₄ 

State whether the following conversion is oxidation or reduction:

Cu²⁺ + 2 e^-→ Cu 

State whether the following conversion is oxidation or reduction:

K → K⁺ + e^- 

State whether the following conversion is oxidation or reduction:

2Cl^- - e^-→ Cl₂ 

In the following reaction: A⁺ + B → A + B⁺. Write half-reactions for this reaction and name:

1. oxidizing agent
2. substance oxidized
3. reducing agent 

Divide the following reactions into oxidation and reduction half-reaction:

Zn + Pb²⁺→ Pb + Zn ²⁺

Divide the following reactions into oxidation and reduction half-reaction:

Zn + Cu²⁺ → Cu + Zn ²⁺

Divide the following reactions into oxidation and reduction half-reaction:

Cl₂ + 2Br^- → Br₂ + 2Cl^-

Write the equation in the ionic form

CuSO4_(aq)  + Fe_(s)→ FeSO4_(aq) + Cu_(s)

Divide the above equation into oxidation and reduction half-reactions.

Give a reason for the following.

Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air.

Give reason:

A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.

Give reason:

Apparatus for laboratory preparation of hydrogen should be airtight and away from a naked flame.

Select the odd one out and justify your answer.

Zn, Fe, Mg, and Na

Select the odd one out and justify your answer.

SO₂, H₂S, NH_3, and CO₃

Select the odd one out and justify your answer.

Fe, Zn, Cu and Mg

Select the odd one out and justify your answer.

Fe, Pb, Al and Zn 

Helium is preferred to hydrogen for filling balloons because it is:

Reacting with water, an active metal produces

A metal oxide that is reduced by hydrogen is

Which of the following statements about hydrogen is incorrect?

For the reaction PbO + H₂→ Pb + H₂O, which of the following statements is wrong?

Which metal gives hydrogen with all of the following: water, acids, alkalis?

Which of the following metals does not give hydrogen with acids?

Choose terms from the options given in brackets to complete this sentence.

When CuO reacts with hydrogen,………………… is reduced and ……………….is oxidized to ………………….

(CuO, H₂, Cu, H₂O)

Choose terms from the options given in brackets to complete this sentence.

Hydrogen is ………………… soluble in water.

(sparingly, highly, moderately)

Choose terms from the options given in brackets to complete this sentence.

Metals like …………….. , ……………… and ……………… give H2 with steam.

(iron, magnesium, aluminium, sodium, calcium)

Choose terms from the options given in brackets to complete this sentence.

Sodium ………………. reacts smoothly with cold water.

(metal, amalgam, in the molten state)

Choose terms from the options given in brackets to complete this sentence.

A metal …………….. hydrogen in the activity series gives hydrogen with …………… acid or …………… acid.

(above, below, dilute hydrochloric, concentrated hydrochloric, dilute sulphuric). 

Correct the following statement:

Hydrogen is separated from CO by passing the mixture through caustic potash solution.

Correct the following statement:

All metals react with acids to give hydrogen.

Correct the following statement:

Hydrogen is dried by passing it through conc. H₂SO₄.

Correct the following statement:

Very dilute nitric acid reacts with iron to produce hydrogen.

Correct the following statement:

Conc. H₂SO₄ reacts with zinc to liberate hydrogen. 

Name:

an oxidizing agent that does not contain oxygen.

Name: 

a substance that oxidizes concentrated HCl to chlorine.

Name:

a substance that will reduce aqueous Iron(III)ions to iron(II)ions.

Name: 

a liquid that is an oxidizing agent as well as a reducing agent.

Name:

a gas that is oxidizing as well as a reducing agent.

Name: 

a solid that is an oxidizing agent.