I know that acetals can be hydrolyzed with H2SO4 but I am not sure how benzaldehyde would be formed following hydrolysis of the cyanohydrin. When I searched online it I found answers suggesting that a carboxylic acid functional group will form rather than benzaldehyde but this question indicated otherwise. Can someone please provide a mechanism as to how benzaldehyde can be reformed after reaction with H2SO4?
Cyanohydrins are formed under acid conditions in the presence of cyanide - essentially the addition of HCN across the C=O bond. Mechanism from Wikipedia
Cyanohydrins are stable under acidic conditions, but note that the reactions are reversible. Under basic conditions (eg carbonate work up of the hydrolysis reaction) the reaction runs backwards losing cyanide anion and regenerating the carbonyl compound