Which among the following salt solution in water shows $\mathrm{pH}$ less than 7 ?

Which among the following salt solution in water shows $\mathrm{pH}$ less than 7 ?
  1. $\mathrm{CuCl}_2$
  2. $\mathrm{CH}_3 \mathrm{COONH}_4$
  3. $\mathrm{Na}_2 \mathrm{CO}_3$
  4. $\mathrm{KNO}_3$

Solution

$\begin{aligned} & \mathrm{CuCl}_2 \rightarrow \text { Salt of } \mathrm{SA}+\mathrm{WB}\left(\text { Acidic } \mathrm{P}^{\mathrm{H}} < 7\right) \\ & \mathrm{CH}_3 \mathrm{COONH}_4 \rightarrow \text { Salt of WA }+\mathrm{WB}\left(\text { Neutral } \mathrm{P}^{\mathrm{H}}=7\right) \\ & \mathrm{Na}_2 \mathrm{CO}_3 \rightarrow \text { salt of WA }+\mathrm{SB}\left(\text { Basic } \mathrm{P}^{\mathrm{H}}>7\right) \\ & \mathrm{KNO}_3 \rightarrow \text { Salt of SA }+\mathrm{SB}\left(\text { Neutral } \mathrm{P}^{\mathrm{H}}=7\right)\end{aligned}$

Asked in: MHT CET 2021 (23 Sep Shift 2)

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