An unknown sample was crystallized from benzene. on cooling to 0 degree centigrade in an ice bath the amount of crystals in flask was quite large, but much of it seemed to disappear when an attempt was made to collect it by suction filtration. Explain?
3 answers
My guess it had a high vapor pressure as a solid (like moth balls) and sublimed under suction.
Since benzene has low melting point of 6 degrees , on cooling the soln to 0°c crystals formed since it was lower than m.p of benzene then on atempt of filtration the temp raised aproaching the mp of benzene hence crystals disappear again.
During suction filtration the crystals prepared from benzene disappeared due, the high speed and pressureof the vacuum filter to absorb the smallest particles of a crystals and the high vapour of a benzene cause a crystal to evaporate when was in a vacuum filter.