Question

Which of the following is soluble in water?
A) Ghee
B) Curd
C) Blood
D) Sugar

Answer 1

Non-polar substances do not dissolve in polar substances due to absence of hydrogen bonding, they lack the ability to interact with the polar molecules of the solvent.
While in case of polar substances, they readily dissolve in polar solvents as they break the polar bonds present between the constituent molecules of the solvent.

Complete solution:
In order to answer this question, we will have to consider the conditions which are necessary for a compound to be soluble in water.
We know that water is a polar molecule, and if another polar compound is added to water it could break the hydrogen bond present between the water molecules, and so it would become soluble in water. Some other factors like temperature pressure also determine the extent of solubility of a substance in a solvent which is water in this case. But, in this question, we wouldn’t need these factors.
We will consider each of the options which are provided to us in the question, and compare them with each other, and see if they are soluble in water or not.
In the first option, ghee is present and we know that it is a nonpolar substance, it cannot interact with the water molecules as the water molecules are polar in nature. So, the molecules of Ghee or oil would float on the surface of water, hence insoluble. So, option A is incorrect.
As per the option B, curd is nothing but a condensed form of milk. When we mix curd in water it forms a colloidal solution at first and the particles will spread out in the water forming a solution. Hence it is soluble in water. So, option B is correct.
Now, if we consider the next option, it asks if blood is soluble in water or not. We know that blood is a colloidal solution which is composed of red blood cells which float in the liquid plasma. By the addition of this blood in water, the particles of blood get dispersed in water forming a solution. Hence, it is soluble in water.
Now, the last option is sugar, and it is a polar molecule. So, as we have discussed above, it will interfere with the hydrogen bonding present between water molecules and so it will become soluble in water. So this option is also correct.

So, options B, C and D are the correct answer.

Note: Ghee is a nonpolar substance so it won’t be miscible in water. Curd and blood are colloids, so their particles will get dispersed when added to water, and the solution becomes dilute. As per the molecules of sugar, they are polar substances, so they would break the Hydrogen bonding present between the water molecules so they will be soluble.