Preparation of Hydrogen from Cold Water and Metals

Q. Question 5.4
Translate the following statement into chemical equation and then balance it:

Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Q. Question 3

What happens when dilute hydrochloric acid is added to iron filings?

Q.

Name the elements that are in liquid state at room temperature.

Q.

When dilute $\mathrm{HCl}$ reacts with Zinc metal, which gas is liberated?

Q. Question 3
Why does dry HCl gas not change the colour of dry litmus paper?

Q.

Write the chemical equation for potassium reacting with cold water

Q. One mole of N2 gas at 0.8 ATM takes 38 sec to diffuse through a pin hole, where as one mole of an unknown compound of Xenon with F at 1.6 ATM takes 57 sec to diffuse through the same hole. Calculate the molecular formula of the compound

Q.

Write balanced chemical reaction between Magnesium metal with steam .

Q.

Question 6
What happens when calcium is treated with water?

(i) It does not react with water.
(ii) It reacts violently with water.
(iii) It reacts less violently with water.
(iv) Bubbles of hydrogen gas formed stick to the surface of calcium.

a) (i) and (iv) (b) (ii) and (iii)

(c) (i) and (ii) (d) (iii) and (iv)

Q.

Which of the following metal on reaction with cold water liberates hydrogen gas but does not float on water?

1. Gold (Au)

2. Zinc (Zn)

3. Sodium (Na)

4. Calcium (Ca)

Q.

Complete and balance the following reactions.

(a) $Na+H_{2}O\to$ _________ + _________

(b) $Ca+H_{2}O\to$ __________+_________

(c) $Mg+H_{2}O\to$ __________+_________

(d) $Zn+H_{2}O\to$ ___________+_________

(e) $Fe+H_{2}O\to$____________+_________

(f) $Zn+HCl\to$ _____________+__________

(g) $Al+H_{2}S{O}_4\to$__________+_________

(h) $Fe+HCl\to$___________+____________

(i) $Zn+NaOH\to$ __________+____________

(j) $Al+KOH+H_{2}O$ _________+____________

Q.

Lead (II) oxide reacts with hydrogen to form

1. Lead hydride and oxygen

2. Lead hydroxide

3. Lead and water

4. Lead and hydrogen peroxide

Q.

A large piece of zinc metal is placed in a copper (II) sulfate, $CuS{O}_4$ solution. The blue solution becomes colourless as copper metals fall to the bottom of the container. The resulting solution contains zinc sulfate, $ZnS{O}_4$. Write a balanced chemical equation for the reaction.

Q. Identify the gas which is liberated when a reactive metal reacts with an acid.

1. Oxygen
2. Hydrogen
3. Carbon dioxide
4. Carbon monoxide

Q.

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

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

(b) Write an equation for the reaction.

(c) What do you observe when a few drops of red litmus solution are added to the turbid solution ?

Q.

Complete the following word equations :

(a) Sodium hydroxide + zinc $\to$ hydrogen +......................

(b) Calcium +water $\to$ calcium hydroxide+...............

Q.

Give reasons for the following.

Hydrogen is used to weld metals.

Q.

Name two alkalies that can displace hydrogen. Give balanced equations for the same. Why are the metals you have used considered to have unique nature.

Q.

Which metal is preferred for collecting hydrogen from :

(a) cold water ?

(b) hot water ?

(c) steam ?

Write balanced equation for each case.

Q.

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

(a) a monovalent metal

(b) a divalent metal.

Q.

Why hydrogen is not prepared in the laboratory by the action of sodium with cold water?

Q.

Which of the following reaction can produce boron nitride BN

1. 

2. 

3. 

4. All the above

Q.

Potassium reacts with water to produce _______ flame.

1. Lilac

2. Yellow

3. Red

4. Green

Q. Balance the given reaction.$S+HN{O}_3\to H_{2}S{O}_4+N{O}_2+H_{2}O$

Q.

What happens when a piece of zinc metal is added to copper sulphate solution? Also, write the balanced chemical equation if the reaction occurs

Q.

Question 9(a)
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
(a) neutral?
Arrange the pH in increasing order of hydrogen-ion concentration.

Q. Calculate the number of atoms in 1)1mole of nitrogen 2)1mole of phosphorus molecules 3)0.05g of water Calculate the number of molecules in 1ml of oxygen at NTP

Q.

Hydrogen can be obtained from water by

1. Reaction with metal oxides

2. Reaction with non-metal oxides

3. Reaction with metals

4. Reaction with metal hydrides

Q.

The pH of a solution is found to be 5.5. What is the nature of the solution?

1. Acidic

2. Basic

3. Neutral

4. Difficult to determine

Q. Question 2
Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?