Question

Complete the following chemical reactions.
`(i) PbS(s)+H_(2)O_(2)(aq) to `
(ii) `(ii) MnO_(4)^(-)(aq)+H_(2)O_(2)(aq) to `
`(iii) CaO(s)+H_(2)O(g) to `
`(iv) AlCl_(3)(g)+H_(2)O(l)to `
`(vi) Ca_(3)N_(2)(s)+H_(2)O(l)to `
Classify the above into (a) hydrolysis, (b) redox and (c) hdydration reactions.

Answer 1

`(i) PbS_(s)+H_(2)O_(aq) to PbSO_(4_(s))+H_(2)O_(l)`
`H_(2)O_(2)` is acting as an oxidizing agent in the reaction. Hence, it is a redox reaction.
(ii) `2MnO_(4_(aq))+5H_(2)O_(2_((s))) to 6H_(aq)^(+) to 2Mn_(aq)^(2+)+8H_(2)O_(l)+5O_(2_(s))`
`H_(2)P_(2_(aq))` is acting as a reducing agent in the acidic medium, thereby oxidizing. Hence, the given reaction is a redox reaction.
(iii) `CaO_(s)+H_(2)O_(s) to Ca(OH)_(2_(sq)`
The reactions in which a compound reacts with water to produce other compounds are called hydrolysis reactions. The given reaction is hydrolysis.
(iv) `2AlCl_(s_(aq))+3H_(2)O_(l) to Al_(2)O_(3_(s))+6HCl_(aq)`
The reactions in which a compound reacts with water to produce other compounds are called hydrolysis reactions. The given reaction represents hydrolysis of AlCl3.
`Ca_(2)N_(2_(s))+6H_(2)O_(l) to 3Ca(OH)_(2_(aq))+2NH_(3_(g)`