Question

Why is cobalt chloride paper is kept in a jar with a ground glass stopper?

Answer 1

Answer:

There is a change in the colour of cobalt chloride paper clipped on the lower surfaces of the leaf  indicates loss of water vapour from this surface through transpiration. Cobalt chloride paper is pink when moist and blue when dry. The rate of loss of water is, however, more on the lower side than the upper side.