Question

Write following electron transfer half equations: 1) Barium reacts with dilute nitric acid 2) Lithium reacts with dilute sulfuric acid?

Answer 1

`2Li(s) + H_2SO_4(aq) rarr Li_2SO_4(aq) + H_2(g)uarr`

Explanation:

`Ba(s) + 2HNO_3(aq) rarr Ba(NO_3)_2(aq) + H_2(g)uarr`

Both of these are redox reactions. Which species are oxidized, and which species are reduced? Can you write equivalent reactions for lithium metal and nitric acid, and barium metal and sulfuric acid? Note that `BaSO_4` is quite insoluble in water.

Of course the half equations are:

`(i)` `Li(s) rarr Li^(+) + e^(-)`

`(ii)` `Ba(s) rarr Li^(+) + 2e^(-)`

The corresponding reduction equation is:

`H_2O +e^(-) rarr 1/2H_2 + HO^-`

Are charge and mass balanced in each instance?