100 mL of 0.5 M HCl is mixed with 100 mL of 0.5 M NaOH in an insulated vessel. Take Delta H_neut=-57.1 kJ mol^-1, total mass of solution 200 g and specific heat 4.18 J g^-1K^-1. The temperature rise is closest to

JEE Main levelSingle correct optionDifficulty 2 of 3td135

$100 mL$ of $0.5 M$ HCl is mixed with $100 mL$ of $0.5 M$ NaOH in an insulated vessel. Take $Δ H_{n e u t} = - 57.1 kJ mo l^{- 1}$ , total mass of solution $200 g$ and specific heat $4.18 J g^{- 1} K^{- 1}$ . The temperature rise is closest to

Moles of water formed

= 0.100 \times 0.5 = 0.050 mol

, heat

= 0.050 \times 57100 = 2855 J

Δ T = 2855/ (200 \times 4.18) = 3.42 K

, about

3.4 K

. Using only

100 g

gives

6.8 K

, and

1.7 K

and

13.7 K

come from a wrong mole count or mass.