Assignment 4
1. What will be the action of the following substances on litmus paper? Dry HCl gas,
Moistened NH3 gas, Lemon juice, Carbonated soft drink, Curd, Soap solution.
88. Name the acid present in ant sting and give its chemi al formula. Also give the common
method to get relief from the discomfort caused by the ant sting.
2. A student prepared solutions of (i) an acid and ( i) a base in two separate beakers. She
forgot to label the solutions and litmus paper is not available in the laboratory. Since both
the solutions are colourless, how will sh distinguish between the two?
3. How would you distinguish between baking powder and washing soda by heating?
4. Salt - A commonly used in bakery products on heating gets converted into another salt B
which itself is used for removal of hardness of water and a gas C is evolved. The gas C
when passed through lime water, turns it milky. Identify A, B and C.
5. In one of the industrial proce ses used for manufacture of sodium hydroxide, a gas X is
formed as by product. The gas X reacts with lime water to give a compound Y which is
used as a bleaching agent in chemical industry. Identify X and Y giving the chemical
equation of the reactions involved.
6. What are strong and weak acids? In the following list of acids, separate strong acids from
weak acids. Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric
acid.
7. When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is
utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of
the reaction involved and also write a test to detect the gas formed.
8. For making cake, baking powder is taken. If at home your mother uses baking soda instead
of baking powder in cake,
(a) how will it affect the taste of the cake and why?
(b) how can baking soda be converted into baking powder?
(c) what is the role of tartaric acid added to baking soda?
9. A metal carbonate X on reacting with an acid gives a gas which when passed through a
solution Y gives the carbonate back. On the othe hand, a gas G that is obtained at anode
during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting
drinking water. Identity X, Y, G and Z
10. A dry pellet of a common base B when kept in open absorbs moisture and turns sticky.
The compound is also a by–product of chloralkali process. Identify B. What type of
reaction occurs when B is treated with an acidic oxide? Write a balanced chemical equation
for one such solution.
11. A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance, which
can be moulded into different shapes by making its dough. When this compound is left in
open for some time, it becomes a solid mass and cannot be used for moulding purposes.
Identify the sulphate salt and why does it show such a behaviour? Give the reaction
involved
1. What will be the action of the following substances on litmus paper? Dry HCl gas,
Moistened NH3 gas, Lemon juice, Carbonated soft drink, Curd, Soap solution.
88. Name the acid present in ant sting and give its chemi al formula. Also give the common
method to get relief from the discomfort caused by the ant sting.
2. A student prepared solutions of (i) an acid and ( i) a base in two separate beakers. She
forgot to label the solutions and litmus paper is not available in the laboratory. Since both
the solutions are colourless, how will sh distinguish between the two?
3. How would you distinguish between baking powder and washing soda by heating?
4. Salt - A commonly used in bakery products on heating gets converted into another salt B
which itself is used for removal of hardness of water and a gas C is evolved. The gas C
when passed through lime water, turns it milky. Identify A, B and C.
5. In one of the industrial proce ses used for manufacture of sodium hydroxide, a gas X is
formed as by product. The gas X reacts with lime water to give a compound Y which is
used as a bleaching agent in chemical industry. Identify X and Y giving the chemical
equation of the reactions involved.
6. What are strong and weak acids? In the following list of acids, separate strong acids from
weak acids. Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric
acid.
7. When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is
utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of
the reaction involved and also write a test to detect the gas formed.
8. For making cake, baking powder is taken. If at home your mother uses baking soda instead
of baking powder in cake,
(a) how will it affect the taste of the cake and why?
(b) how can baking soda be converted into baking powder?
(c) what is the role of tartaric acid added to baking soda?
9. A metal carbonate X on reacting with an acid gives a gas which when passed through a
solution Y gives the carbonate back. On the othe hand, a gas G that is obtained at anode
during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting
drinking water. Identity X, Y, G and Z
10. A dry pellet of a common base B when kept in open absorbs moisture and turns sticky.
The compound is also a by–product of chloralkali process. Identify B. What type of
reaction occurs when B is treated with an acidic oxide? Write a balanced chemical equation
for one such solution.
11. A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance, which
can be moulded into different shapes by making its dough. When this compound is left in
open for some time, it becomes a solid mass and cannot be used for moulding purposes.
Identify the sulphate salt and why does it show such a behaviour? Give the reaction
involved
