Question

While preparing w/w 50% NaOH solution I noticed a decrease in solution volume (5-10mL) in a 2L volumetric flask, so I am wondering if there is an increase in water volume during the water evaporation or concentration of NaOH? Is it the same amount and is it measurable?

QuantumYitian question regarding the decrease of volume during the dissolution of NaOH

Answer 1

When preparing a % w/w NaOH solution, the decrease in solution volume is caused by water evaporation. The decrease is small, ranging from 5-10mL, and can be measured if the starting and final volumes are accurately recorded.

Step-by-step explanation:

When preparing a % w/w NaOH solution, it is normal to experience a decrease in solution volume due to water evaporation. As the solution is exposed to the air, some of the water in the solution evaporates, leading to a decrease in volume.

This is because water has a higher vapor pressure compared to sodium hydroxide, causing it to evaporate more readily. The decrease in volume is usually small, ranging from 5-10 mL, and can be measured if the starting and final volumes are accurately recorded.