Recall Kjeldahl's method

Kjeldahl's method is used to estimate nitrogen in organic compounds.

In this method, the organic compound is heated with concentrated $\mathrm{H_2SO_4}$ so that nitrogen is converted into ammonium sulfate.

Role of additives in digestion

During digestion, certain substances are added:

• $\mathrm{K_2SO_4}$: raises the boiling point of sulfuric acid, making digestion faster.
• $\mathrm{CuSO_4}$: helps speed up the oxidation/digestion process.

Therefore, $\mathrm{CuSO_4}$ functions as a catalyst.

Check options

• A: catalytic agent $\rightarrow$ Correct
• B: hydrolysis agent $\rightarrow$ Incorrect
• C: reducing agent $\rightarrow$ Incorrect
• D: oxidising agent $\rightarrow$ Incorrect

Final answer

In Kjeldahl's method, $\mathrm{CuSO_4}$ acts as a catalytic agent.