2
$\begingroup$

$$\ce{NaCl + H2SO4 -> NaHSO4 + HCl}$$

The above reaction happens, but why doesn't the following happen? Or does it but only when one of the reactants is in excess?

$$\ce{2NaCl + H2SO4 -> Na2SO4 + 2HCl}$$

The second reaction seems plausible to me. How can I predict whether a similar type of reaction will be like the first equation or the second equation?

$\endgroup$
3
$\begingroup$

Sodium bisulphate (pKa ~ 2 - https://en.wikipedia.org/wiki/Sulfuric_acid) is a much weaker acid that hydrochloric acid (pKa = ~ -7), which means that chloride is not a strong enough base to deprotonate sodium bisulphate.

However all acid pbased reactions are at equilibrium. Roughly one part in 10^9 of the species involve sulphate anion, which for all practical purposes is negligible.

Table of pKa charts: http://www.lauher.com/che142/acidbase.pdf

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.