Classical Idea of Redox Reactions

When $\mathrm{P}$reacts with caustic soda, the products are ${\mathrm{PH}}_3$ and ${\mathrm{NaH}}_2{\mathrm{PO}}_2$. This reaction is an example of

Give an example to demonstrate reduction w.r.t addition/removal of an electropositive element.

What is ozone hole? Give some harmful effects of ozone hole.

Oxidation is defined as the addition of _____ element to a substance or removal of hydrogen/ electropositive element from a substance.

Give an example for oxidation.

Oxidation is defined as the addition of an electronegative element to a substance or removal of an electropositive element from a substance.

With the depletion of the ozone layer, UV radiations lead to ageing of the skin, cataracts, sunburn, skin cancer, killing of many phytoplanktons, damage to _____ productivity etc.

With the depletion of ozone layer, more UV radiation filters into stratosphere.

What are the effects of depletion of the ozone layer?

What happens to the solution of ferric chloride acidified with $\mathrm{HCl}$, when hydrogen is bubbled through it?

A solution of ferric chloride acidified with $\mathrm{HCl}$ is unaffected when hydrogen is bubbled through it.

A solution of ferric chloride acidified with $\mathrm{HCl}$ is unaffected when hydrogen is bubbled through it, but gets reduced when $\mathrm{Zn}$ is added to same acidified solution. Why?

What will be the main product in the reaction happens between potassium ferrocyanide and hydrogen peroxide?

Which of the following will be the equation for the reaction happens between potassium ferrocyanide and hydrogen peroxide?

Define redox reactions based on the electropositive part? 

Discuss how does the reduction reaction involved in alkenes.

Express the definition of reduction based on the classical concept.

Write a reaction for the classical concept of the reduction.

The reduction reaction is stated as the addition more electropositive element.

Define reduction based on the classical concept.