Explain the principle and estimation method for carbon and hydrogen in an organic compound.

(N/A) Principle: Carbon and hydrogen in an organic compound are estimated by burning a known mass of the compound in the presence of excess oxygen and copper $(II)$ oxide $(CuO)$. Carbon is oxidized to carbon dioxide $(CO_2)$ and hydrogen is oxidized to water $(H_2O)$.
Reaction: $C_xH_y + (x + \frac{y}{4})O_2 \rightarrow xCO_2 + \frac{y}{2}H_2O$
Procedure:
$1$. $A$ known mass $(m \ g)$ of the organic compound is placed in a platinum boat and burnt in a combustion tube in the presence of excess oxygen and $CuO$.
$2$. The resulting gases are passed through a weighed $U$-tube containing anhydrous calcium chloride $(CaCl_2)$,which absorbs water.
$3$. The gases are then passed through another weighed $U$-tube containing a concentrated solution of potassium hydroxide $(KOH)$,which absorbs carbon dioxide.
Calculation:
- Let the increase in mass of the $CaCl_2$ $U$-tube be $m_1 \ g$ (mass of $H_2O$ produced).
- Let the increase in mass of the $KOH$ $U$-tube be $m_2 \ g$ (mass of $CO_2$ produced).
Percentage of Hydrogen: Since $18 \ g$ of $H_2O$ contains $2 \ g$ of hydrogen,
$\text{Percentage of } H = \frac{2 \times m_1 \times 100}{18 \times m}$
Percentage of Carbon: Since $44 \ g$ of $CO_2$ contains $12 \ g$ of carbon,
$\text{Percentage of } C = \frac{12 \times m_2 \times 100}{44 \times m}$