Which of the following is considered to be a dangerous procedure in the laboratory setting?
a. pouring all liquids, especially acids and bases, over the sink
b. wearing goggles
c. pushing glass tubing, thermometers, or glass thistle tubes through a rubber cork
d. pointing the mouth of a test tube that is being heated away from you and others
e. knowing where the fire extinguisher and eyewash stations are located

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.