Question

50.0 mL of a solution of HCl is combined with 100.0 mL of 1.05M NaOH in a calorimeter. The reaction mixture is initially at 22.4 degree C, and the final temperature after reaction is 30.2 degree C. What is the molarity of the HCl solution? You may assume that there is an excess of base (so that all the HCl has reacted), that the specific heat of the reaction mixture is 0.96 cal/g degree C, and that the density of the reaction mixture is 1.02 g/mL. The heat of neutralization of HC1 and NaOH is 13.6 kcal/mole.

Answer 1

Answer:

2.1 M is the molarity of the HCl solution.

Explanation:

$HCl+NaOH\rightarrow H_2O+NaCl$

Molarity of HCl solution = $M_1=?$

Volume of HCl solution = $V_1=50.0mL$

Ionizable hydrogen ions in HCl = $n_1=1$

Molarity of NaOH solution = $M_2=1.05 M$

Volume of NaOH solution = $V_2=100.0 mL$

Ionizable hydroxide ions in NaOH = $n_2=1$

$n_1M_1V_1=n_2M_2V_2$ (neutralization )

$M_1=\frac{M_2V_2}{V_1}=\frac{1.05M\times 100.0 mL}{50.0 mL}$

$M_1=2.1 M$

2.1 M is the molarity of the HCl solution.