Question

Which solution has the lowest pH?

• A. $0.010$ - molar $HCl$
• B. $0.010$ - molar $NaOH$
• C. $0.010$ - molar $Ba(OH{)}_2$
• D. $0.010$ - molar $H_{2}S{O}_4$
• E. $0.010$ - molar $C_{12}{H}_{22}{O}_{11}$ (cane sugar)

Answer 1

Answer: (A)

$0.010$ - molar $HCl$

Lowest $P^H$ corresponds to the strong acid which has very high value of ionization constant.

Since, ionisation of $HCl$ > ionisation of $H_2{SO}_4$. So $HCl$ will have lower $P^H$ under same concentration.