Formation Of Anhydride

How many of the following compounds are anhydrides?

Which reaction is not possible for acetic anhydride?

Iupac Rules For Anhydrides

x = moles of anhydride consumed

Which of the following is an anhydride ?

Which of the following is not an acid anhydride ?

Three isomeric tetracarboxylic acids (I),(II) , and (III) are given. They can be distinguised by anhydride formation by treating with one equivalent and two equivalents of SOCl_2 . Which tetracarboxylic acid on reaction with one equivalent of SOCl_2 gives two isomeric monoanhydrides ?