Question

In the detection test of carbon and hydrogen with cupric oxide, carbon is oxidized to:

• A. Carbonic Acid
• B. Carbon Dioxide
• C. Carbon Monoxide
• D. Copper Sulphate

Answer 1

The correct option is B

Carbon Dioxide

Explanation:

Option (B) Carbon Dioxide

Liebig’s Method:

• This method is used for the estimation of carbon and hydrogen in an organic compound.
• The organic compound gets heated in presence of dry Cupric oxide and the oxidation of elements into their oxides takes place.
• Then, the organic compound of known mass is strongly heated in presence of dry Cupric oxide $\left(\mathrm{CuO}\right)$.
• The reaction involved is: $\underset{\mathrm{Carbon}}{\mathrm{C}\left(\mathrm{s}\right)}+\underset{\mathrm{Cupric}\mathrm{oxide}}{2\mathrm{CuO}\left(\mathrm{s}\right)}\stackrel{∆}{\to }\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Copper}}{2\mathrm{Cu}\left(\mathrm{s}\right)}$
• These oxidized products are absorbed by the Calcium hydroxide or Lime water $\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$ and anhydrous Copper sulfate ${\mathrm{CuSO}}_4$.
• If the Copper sulfate turns blue due to the formation of ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$ (water vapor) then the compound contains Hydrogen. The hydrogen oxidized to water and it changes the color of anhydrous copper sulfate from colorless to blue.
• If the lime water is turned milky by carbon dioxide, then the compound contains carbon, which means the carbon is oxidized to Carbon dioxide.
• Hence, in Liebig’s method, or the estimation of carbon, the Copper oxide oxidizes the carbon to the Carbon dioxide.

Therefore, option (B) is the correct answer. In the detection test of carbon and hydrogen with cupric oxide, carbon is oxidized to Carbon dioxide.