Answer:
The water level in the buret will drop when the temperature of the solvent system is increased by grasping the buret with your hand. This is because an increase in temperature will cause an increase in the vapor pressure of the volatile liquid.
As the temperature of the solvent increases, the vapor pressure of the volatile liquid will also increase. This means that the liquid will more readily evaporate, creating more gas molecules in the space above the liquid. Because the buret is sealed, the increased number of gas molecules will push the liquid level down, causing the water level in the buret to drop.
This behavior is due to the increase in vapor pressure of the volatile liquid with an increase in temperature. The volatile liquid will be less dense when temperature increases and more molecules of the liquid will be converted into gas. This decrease in density will cause the liquid level to drop, and the increase in vapor pressure will cause the liquid to evaporate more readily.