Question

3. In which reaction hydrogen gas is released?
(i) H2O + K→
(ii) HCl + Zn→
(iii) H2 SO4 + Cu →
(iv) HNO3 + Fe →
(a) i ,ii, iii (b) i & ii (c) i ,ii,iv (d) All of them.
4. In an experiment there are four containers A,B,C and D . Different
components of the containers given below –
Container A – air tight Plaster of Paris.
Container B – plaster of Paris and moist air.
Container C – plaster of Paris, moist air and calcium chloride
Container D – plaster of Paris and dry air.
In which of the following container you will observe formation of solid mass –
(a) B,C & D (b) B & C (c) A , B & C (d) B only.

Answer 1

Answer:

I, ii, iii is the anwer of 3 and 4 I don't know