Page 229 - Chemistry ICSE Class IX

Chemistry Practicals 217

VIVA VOCE

1. Name three anions which react with dilute sulphuric acid.
2–
Ans. Carbonate ion (CO 2– ), Sulphide ion (S ), Sulphite ion (SO 2– ).
3 3
2. Name the gases which evolve when the following salts are reacted with dilute sulphuric acid: Sodium carbonate, Iron
sulphide, Sodium sulphite
Ans. The gases evolved when the given salts react with dilute sulphuric acid are:
Salt Sodium carbonate Iron sulphide Sodium sulphite
Gas evolved Carbon dioxide (CO ) Hydrogen sulphide (H S) Sulphur dioxide (SO )
2 2 2
3. Which of the given gases smells like rotten eggs: CO , H S or SO ?
2 2 2
Ans. H S smells like rotten eggs.
2
4. Name the reagent used for detecting sulphur dioxide gas.
Ans. Acidified potassium dichromate solution [K Cr O (aq)].
2 2 7
5. Write the test used for identifying hydrogen sulphide.
Ans. To identify hydrogen sulphide gas, lead acetate solution is used. Hydrogen sulphide turns lead acetate solution black.
6. Write chemical equation for the reaction of iron sulphide with dilute sulphuric acid.
Ans. FeS(s) + H SO (aq) o FeSO (aq) + H S(g)
2 4 4 2
iron sulphide hydrogen sulphide
7. Give an example of hydrogen displacement reaction.
Ans. Active metals, such as Mg and Zn, displace hydrogen from dilute acids/acid solutions.
Mg(s) + H SO (aq) o MgSO (aq) + H (g)
2 4 4 2
magnesium