Acid chlorides can be prepared from carboxylic acids by treatment with

a) pbr3
b) socl_2
c) kcl
d) both a and b
e) both b and c

D

Explanation:

Both thionyl chloride and phosphorus trichloride are used in the synthesis of acid chlorides from carboxylic acids. The thionyl chloride leads to a chlorosulphite intermediate before the acid chloride is formed

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.