Question

You are supplied with five solutions : A, B, C, D and E with $p^H$ values as follows:

A = 1.8, B = 7, C = 8.5, D = 13, and E = 5

Classify these solutions as neutral, slightly or strongly acidic and slightly or strongly alkaline.

Which solution would be most likely to liberate hydrogen with :

(a) magnesium poweder,

(b) powdered zinc metal. Give a word equation for each reaction.

Answer 1

neutral -> B
strongly alkaline -> D
strongly acidic -> A
slightly/weakly acidic -> E
Slightly/weakly alkaline -> C

The arrangement of pH in increasing order of hydrogen-ion concentration is 13<8.5<7<5<1.8


Both the metal or metal powder liberates hydrogen gas when reacts with hydrochloric acid.
Mg + 2 HCl ----> MgCl2 + H2
Zn + 2 HCl ----> ZnCl2 + H2
But the second reaction occur more than the first one because zinc is more reactive metal than magnesium