$A$ solution of sodium chloride in contact with the atmosphere has a $pH$ of about

$pH$ of an aqueous solution of $NH_4Cl$ is

Which of the following salts will give the highest $pH$ in water?

What will be the $pH$ of an aqueous solution of $1.0 \ M$ ammonium formate? (Given: $pK_a = 3.8$ and $pK_b = 4.8$)

Which of the following is an acidic salt?

$20\,mL$ of $0.1\,M\,NH_{4}OH$ is mixed with $40\,mL$ of $0.05\,M\,HCl$. The $pH$ of the mixture is nearest to. (Given: $K_{b}(NH_{4}OH) = 1 \times 10^{-5}, \log 2 = 0.30, \log 3 = 0.48, \log 5 = 0.69, \log 7 = 0.84, \log 11 = 1.04$) (in $.2$)