A covalent molecule having a double bond between its atoms is:

61 If the number of protons in one atom of an element Y is 20, then the number of electrons in its ion Y²⁺ will be: 62 The noble gas having only two electrons in its valence shell is: 64 The molecules having triple bond in them are: 65 One of the following contains a double bond as well as single bonds. This is: