Number of isomeric products formed by monochlorination of 2-methylbutane in presence of sunlight is ________.

In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is $$(+)$$ _________.

A compound $$(x)$$ with molar mass $$108 \mathrm{~g} \mathrm{~mol}^{-1}$$ undergoes acetylation to give product with molar mass $$192 \mathrm{~g} \mathrm{~mol}^{-1}$$. The number of amino groups in the compound $$(x)$$ is ___________.