In which of the following states is Pichola Lake

The most reactive among the halogens is-

The element used in the manufacture of safety matches is —

The nucleus of an atom consists of-

The gas used for filling weather balloons is-

The fuel that is used in modern submarines is -

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

Petroleum is a mixture of-

Which of the following is a physical change?

Urea is a —

___________ is the process in which acids and bases react to form salts and water.