Question

Glucose or sucrose are soluble in water in water but cyclohexane not

Answer 1

For any compound to be water soluble, it should develop dipoles (partial negative & partial positive charges at the two ends of compound. The development of charges results in the formation of hydrogen bond between the water molecule & the compound. The development of charges at two ends is due to the difference in the electronegativity between two atoms. The atom with higher electronegativity will acquire negative charge while the atom with lower electronegativity will acquire positive chargeA glucose molecule contains five –OH (highly electronegative) groups while a sucrose molecule contains eight −OH groups. Thus, glucose and sucrose undergo extensive H-bonding with water.Hence, these are soluble in water.

But cyclohexane and benzene do not contain −OH groups. They contain only Carbon & hydrogen atoms,as a result the dipole developed is very weak in nature & hence the hydrogen bond formed is not strong. Hence, they cannot undergo H-bonding with water and as a result, are insoluble in water.

Answer 2

$\huge\texttt{Answer :-}$

Glucose and sucrose are polar in nature and hence are soluble in water. On the other hand cyclohexane and benzene are non-polar and hence are not soluble in water.

Hence, the question is verified.