Question

identify and then write the balance chemical equation for each salt below that will yield a basic solution in water

i. NH4Br ii. NaCN iii. BaF2 iv. NaNO3

Answer 1

Out of all the four salts given above NaCN will result in to a basic solution in water because it is a salt of weak acid (HCN) and a strong base (NaOH), the balanced chemical equation in water can be wriiten as follows :

NaCN(s) Na+(aq) + CN-(aq)

CN-(aq) + H2O(l) HCN(aq) + OH- (aq)

adding tthe above two equations to get the balanced chemical equation

NaCN(s) + H2O (l) HCN (aq) + NaOH(aq)

(i) NH4Br

     It is a salt of strong acid HBr and a weak base NH4OH. Since HBr is a strong acid so there is no reaction between Br- and H2O . Hence an acidic solution is produced.The balanced equation is written as follows:

NH4Br(s) NH4+(aq) + Br-(aq)

NH4+(aq) + H2O(aq) NH4OH(l) + H+(aq)

Net balanced equation: NH4Br(s) + H2O(aq) NH4OH(l) + HBr(l)

(iii) BaF2

     Barium fluoride is considered as a ionic solid (salt) of a weak acid (HF) and strong base Ba(OH)2. Therefore it will form weakly acidic solution.

2HF(aq) + Ba(OH)2(aq) BaF2(aq) + 2H2O(l)

(iv) NaNO3

     It is a salt of strong acid HNO3 and a strong base NaOH. Therefore results in to a neutral solution.

NaNO3 (s) + H2O (aq) NaOH (s) + HNO3(l)