The main use of litmus is to test whether a solution is acidic or basic. For instance, ammonia gas, which is alkaline, colours the red litmus paper blue.

Correct Option: D

The main use of litmus is to test whether a solution is acidic or basic. For instance, ammonia gas, which is alkaline, colours the red litmus paper blue.

Biodiesel production is the process of producing the biofuel, biodiesel, through the chemical reactions trans-esterification and esterification. This involves vegetable or animal fats and oils being reacted with short-chain alcohols (typically methanol or ethanol).

Correct Option: C

Biodiesel production is the process of producing the biofuel, biodiesel, through the chemical reactions trans-esterification and esterification. This involves vegetable or animal fats and oils being reacted with short-chain alcohols (typically methanol or ethanol).

Methanol is also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits. It acquired the name "wood alcohol" because it was once produced chiefly as a byproduct of the destructive distillation of wood. Modern methanol is produced in a catalytic industrial process directly from carbon monoxide, carbon dioxide, and hydrogen.

Correct Option: A

Methanol is also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits. It acquired the name "wood alcohol" because it was once produced chiefly as a byproduct of the destructive distillation of wood. Modern methanol is produced in a catalytic industrial process directly from carbon monoxide, carbon dioxide, and hydrogen.

The most common source of lead air pollution is from metal processing, but there are other manufacturing and industry sources as well. The highest lead air pollution levels are found near battery manufacturing and iron and other metal producing plants. Lead air pollution is a dangerous form of pollution because of the way lead builds up in our bodies.

Correct Option: C

The most common source of lead air pollution is from metal processing, but there are other manufacturing and industry sources as well. The highest lead air pollution levels are found near battery manufacturing and iron and other metal producing plants. Lead air pollution is a dangerous form of pollution because of the way lead builds up in our bodies.

Sodium carbonate (also known as washing soda or soda ash) is a sodium salt of carbonic acid. In domestic use, it is used as a water softener in laundering. It competes with the magnesium and calcium ions in hard water and prevents them from bonding with the detergent being used. Sodium carbonate can be used to remove grease, oil and wine stains.

Correct Option: C

Sodium carbonate (also known as washing soda or soda ash) is a sodium salt of carbonic acid. In domestic use, it is used as a water softener in laundering. It competes with the magnesium and calcium ions in hard water and prevents them from bonding with the detergent being used. Sodium carbonate can be used to remove grease, oil and wine stains.