The nucleus of an atom consists of-

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

The element used for making solar cells is

The acid used in lead storage cells is-

Which metal is extracted from seawater?

The noble gas used in radiotherapy is

The important ore of aluminium is-

The fuel that is used in modern  submarines is -

A polymeric substance used to make parachute is

Which of the following is a physical change?