Explain why?
(i) Aqueous solution of sodium acetate has pH more than 7.
(ii)Aqueous solution ofcopper sulphate has pH less than 7.
(iii)Aqueous solution ofpottasium nitrate has pH value 7.
Answers
Acid base reactions result in salts with differing pH based on the nature of the acid or base. The explanation for the given pH values are as follows:
1. Sodium acetate is formed from sodium hydroxide, a strong base, and acetic acid, a weak acid. Hence, it will be basic in nature, and will have a pH greater than 7.
2. Copper sulphate is formed from copper hydroxide, a weak base, and sulphuric acid, a strong acid. Hence, it will be acidic in nature and will have a pH less than 7.
3. Potassium nitrate is formed from potassium hydroxide, a strong base, and nitric acid, a strong acid. Hence, it be neutral in nature and will have a pH of 7.
Answer:
(i) Sodium acetate is formed by mixing sodium hydroxide [a strong base] and acetic acid [a weak acid]. So,it is a basic salt and hence it has pH more than 7.
(ii) Copper sulphate is formed by mixing copper hydroxide [a weak base] and sulphuric acid [a strong acid]. So, it is an acidic salt and hence it has pH less than 7.
(iii) Potassium nitrate is formed by mixing potassium hydroxide [a strong base] and nitric acid [a strong acid]. So, it is a neutral salt and hence it has pH value equal to 7.