Consider the following statements regarding diamond

1. It is an allotrope of silicon
2. It is a bad conductor of heat and electricity
3. It is the hardest substance
4. It burns to produce carbon dioxide

Which of the statements given above are correct?

When applied to the affected area, which one of the following will relieve the pain due to ant-bite or bee-sting?

Oxygen and ozone are

Which among the following elements (metals) pollutes the air of a city having a large number of automobiles?

Alum is used as

The metal compound commonly found in Sindoor or kumkum is based on