Explain why aldehydes and ketones react with a weak acid such as hydrogen cyanide but do not react with strong acids such as hcl or h2so4 (other than being protonated by them).

The cyanide ion is a strong nucleophile.

Explanation:

Strong acids

Strong acids like hydrochloric and sulfuric acid dissociate completely in solution.

Because they are strong acids, their conjugate bases are extremely weak bases/nucleophiles.

Thus, they can protonate the carbonyl oxygen, but the conjugate bases cannot act as nucleophiles.

Weak acids

Weak acids like HCN dissociate only slightly in solution.

Because HCN is a weak acid, its conjugate base is a strong nucleophile.

Thus, it generates relatively few hydronium ions, but the cyanide ion is a strong nucleophile that can attack the partially positive carbon and form the cyanohydrin.

RCH=O + CN⁻ ⟶ RCH(CN)O⁻ ⟶ RCH(CN)OH

As the CN⁻ ions react with the aldehyde or ketone, they are removed from solution.

According to Le Châtelier's Principle, more HCN dissociates to replace the CN⁻ ions, and the reaction goes nearly to completion.

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :