Which of the following is a pair of dihydric phenols?

Which compound is used in medicine as barium meal for intestinal x-ray?

If 100 L gas is enclosed in a cylinder, absorbs 302.6 J of heat and expands to 200 L against constant external pressure of 2 atm . Calculate internal energy change of the gas.

What is the molar mass of third member of homologous series if the molar mass of first member is 46 g ?