Question

Which of the following mixing of 1M base and 1M acid leads to the largest increase in temperature?

(1) 30 mL HCl and 30 mL NaOH

(2) 30 mL \(CH_3COOH\) and 30 mL NaOH

(3) 50 mL HCl and 20 mL NaOH

(4) 45 mL \(CH_3COOH\) and 25 mL NaOH

Answer 1

Correct option is : (1) 30 mL HCl and 30 mL NaOH

Higher the number of milli moles of acid or base reacted higher will be temperature rise.

Option (4) \(n_{\text {acid }}\) or \(n_{\text {base }}\) reacted \(=30 \mathrm{~m} \mathrm{~mol}\)

Option (2) \(n_{\text {acid }}\) or \(n_{\text {base }}\) reacted \(=30 \ \mathrm{m\ mol}\)

but less energy will be released by neutralisation reaction of weak acid hence option (2) can not be correct.

Option (3) \(\Rightarrow 20 \mathrm{~m} \mathrm{~mol}\) 

Option (4) \(\Rightarrow 25 \mathrm{~m} \mathrm{~mol}\)