Name one salt which is added to `AgCl` so as to produce cation vacancies.

Name one substance, which acts as a flux.

Name the cord which vibrates in larynx to produce sound

Schottky defects generate an equal number of cation and anion vacancies while doping produces only cation vacancies and not anion vacancies. Why?

Name the method which is very useful for producing semiconductors.

Name one catalyst which is used in the manufacture of sulphuric acid by contact process.

Give one reaction in which SO_2 behaves as a reducing agent.