Question

Give a chemical test to distinguish between :
(a) dilute sulphuric acid and dilute hydrochloric acid.
(b) dilute sulphuric acid and concentrated sulphuric acid.
[4 MARKS]

Answer 1

Each option: 2 Marks

(a) With barium chloride solution, ditutc sulphuric acid gives white ppt. of $BaS{O}_4$, insoluble hi conc. HCI. On the other hand, dil. HCI does not give any ppt. with $BaC{l}_2$.
$BaC{l}_2(aq.)+H_{2}S{O}_4\left(dil\right)\to BaS{O}_4\left(s\right)+2HCI(aq.)$

(b) Dilute sulphuric acid and concentrated sulphuric acid. . 1. On heating with copper chips cone. $H_{2}S{O}_4$ produces pungent smelling gas $S{O}_2$; whereas dilute sulphuric acid does not.
2. On heating with common salt (NaCI), conc. $H_{2}S{O}_4$ produces pungent smelling HCI gas whereas dilute sulphuric acid does not.