Concentrated hydrochloric acid when kept in open air sometimes produces a cloud of white fumes. The explanation for it is that :

Question

( A ) oxygen in air reacts with the emitted $HCl$ gas to form a cloud of chlorine gas
( B ) strong affinity of HCl gas for moisture in air results in forming of droplets of liquid solution which appears like a cloudy smoke.
( C ) concentrated hydrochloric acid emits strongly smelling HCl gas all the time
( D ) due to strong affinity for water, concentrated hydrochloric acid pulls moisture of air towards itself. This moisture forms droplets of water and hence the cloud