Why we write H2 in place of h

Dear student
Since hydrogen is present naturally in the form of diatomic molecule , hence it is always written as

H_{2}

.
Hence it is written as

H_{2}

S o, d u r i n g c h e m i c a l r e a c t i o n h y d r o g e n r e a c t s a s a m o l e c u l e .

Regards