A solution of 500 mL of 0.2 M KOH and 500 mL of 0.2 M HCl is mixed and stirred; the rise in temperature is T1 . The experiment is repeated using 250 mL each of solution, the temperature rise is T2 . Which of the following is true?

Question

A solution of 500 mL of 0.2 M KOH and 500 mL of 0.2 M HCl is mixed and stirred; the rise in temperature is T1 . The experiment is repeated using 250 mL each of solution, the temperature rise is T2 . Which of the following is true? (A)  T1=T2  (B)  T1=2T2  (C)  T1=4T2  (D)  T2=9T1

Tardigrade Admin · Accepted Answer

Suppose heat evolved in 1st case is Q1 and that in the 2nd case it is Q2 . Then Q2=(1/2)Q1 But Q1=1000 T1 and Q2=500 T2 ∴ 500 T2=(1/2)× 1000 T1 i.e., T2=T1

Q. A solution of 500 mL of 0.2 M KOH and 500 mL of 0.2 M HCl is mixed and stirred; the rise in temperature is $T_{1}$ . The experiment is repeated using 250 mL each of solution, the temperature rise is $T_{2}$ . Which of the following is true?

$T_{1} = T_{2}$

$T_{1} = 2 T_{2}$

$T_{1} = 4 T_{2}$

$T_{2} = 9 T_{1}$

Suppose heat evolved in 1st case is $Q_{1}$ and that in the 2nd case it is $Q_{2}$ . Then $Q_{2} = \frac{1}{2} Q_{1}$ But $Q_{1} = 1000 T_{1}$ and $Q_{2} = 500 T_{2}$ $∴$ $500 T_{2} = \frac{1}{2} \times 1000 T_{1}$ i.e., $T_{2} = T_{1}$

Q. A solution of 500 mL of 0.2 M KOH and 500 mL of 0.2 M HCl is mixed and stirred; the rise in temperature is T1​ . The experiment is repeated using 250 mL each of solution, the temperature rise is T2​ . Which of the following is true?

T1​=T2​

T1​=2T2​

T1​=4T2​

T2​=9T1​