Two moles of acetic acid are heated with `P_(2)O_(5)`. The product formed is

What happens when acetic acid is heated with P_(2) O_(5)

Ammonium salt of bezoic acid is heated strongly with P_2O_5 and the product so formed is reduced and then treated with NaNO_2"/"HCl at low temperature. The final compound formed is

Acetic acid on heating with P_2O_5 produces –

Amide on heating with P_(2)O_(5) gives