Question

In which of the following cases of mixing of a strong acid and a strong base each of 1 N concentration would the temperature increase of the solution be the same (assume heat evolved in neutralisation is only used up to increase the temperature of the solution)?

• A. 20 mL acid and 30 mL alkali
• B. 10 mL acid and 10 mL alkali
• C. 35 mL add and 15 mL alkali
• D. 50 mL acid and 50 mL alkali

Answer 1

Answer: (B), (D)

50 mL acid and 50 mL alkali

Points to remember:
$\Rightarrow q=C\times m\times \Delta T$
Let the density of solution be $d$ and $x$ amount of heat is released when 1 ml of each react, then:
$\Delta T=\frac{C\times m}{q}$
$\Delta T=\frac{C\times d\times v}{q}\left(1\right)$
Option A
$\Delta T=\frac{C\times d\times 50}{20x}$
Option B
$\Delta T=\frac{C\times d\times 20}{10x}$
Option C
$\Delta T=\frac{C\times d\times 50}{15x}$
Option D
$\Delta T=\frac{C\times d\times 100}{50x}$
So option D and B show the same value of $\Delta T$