Which of the following aqueous solutions (0.1 M, 298 K) have a pH greater than 7? Given: K_a(HNO2) = 4.5x10^-4, K_a(CH3COOH) = 1.8x10^-5, K_b(NH3) = 1.8x10^-5.

JEE Main levelOne or more correct optionsDifficulty 2 of 3ia012

Which of the following aqueous solutions (0.1 M, 298 K) have a pH greater than 7? Given: $K_{a} (HNO X_{2}) = 4.5 \times 1 0^{- 4}$ , $K_{a} (CH X_{3} COOH) = 1.8 \times 1 0^{- 5}$ , $K_{b} (NH X_{3}) = 1.8 \times 1 0^{- 5}$ .

NaNO X_{2}

is the salt of a weak acid and strong base: basic.

NH X_{4} NO X_{3}

is acidic. For

CH X_{3} COONH X_{4}

K_{a} = K_{b}

, so pH

= 7

exactly, not greater than 7.

K X_{2} CO X_{3}

is basic because

CO X_{3} X^{2 -}

hydrolyses. Hence A and D.