What is the percentage of $H_{2}SO_{4}$ in dilute sulfuric acid (in $\%$)?

What is meant by anodising? How is it done?

Which substance is used for the chemical reduction of metal oxides like chromium and manganese to obtain the metal?

$(a)$ Why does calcium start floating when added to water?
$(b)$ Most metals do not release hydrogen gas when reacting with nitric acid. Why?
$(c)$ Write the chemical equation for the reaction of iron with steam. Name the compound of iron obtained.

In which solvent is sulphur soluble?

Give reasons for the following:
$(a)$ We can store copper sulphate solution in a silver vessel but not silver nitrate solution in a copper vessel.
$(b)$ The reaction of zinc with dilute nitric acid does not produce hydrogen gas.
$(c)$ Food cans are coated with tin rather than zinc.