How many squares are there on a chessboard

Milk tastes sour when kept in the open for sometimes due to the formation of-

The fuel that is used in modern submarines is -

Petroleum is a mixture of-

Milk tastes sour when kept in the open for sometimes due to the formation of-

Which one amongst the following is not a Green House gas?

One of the constituents of tear gas is

Formation of ozone hole is maximum over

______is the process in which acids and bases react to form salts and water

The pH of a neutral solution is —

The element used in the manufacture  of safety matches is —