A decapeptide {relative molar mass 796) on complete hydrolysis gives glycine (relative molar mass 75), alanine and phenylalanine. Glycine constitutes $47.0\%$ of the total mass of the hydrolysed products. The number of glycine units present in the decapeptide is .

Decapeptide mass weight = 796 g/mol

Total bonds to be hydrolyzed per molecule $=(10-1)=9$.

${\mathrm{H}}_2\mathrm{O}$added in total weighs $=9\times 18=162\mathrm{g}/\mathrm{mol}$

Total weight of the hydrolysis product is 796 + 122 = 958 g.

Total weight of glycine in the product is $=\frac{958\times 47}{100}\mathrm{g}=450\mathrm{g}$

Glycine has a molecular weight of 75g/mol.

Glycine number $=\frac{450}{75}=6$.