Which of the following metals cannot replace hydrogen from water or steam?

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment

The derivative of benzene that can be used in making explosives is

In electrovalency, the oxidation number of the participating metal is always