There is lesser dissociation of hydrogen cyanide as compared to HCl, as equilibrium constant for the dissociation of hydrogen cyanide has been smaller than HCl. Hence, option C is correct.
Hydrogen cyanide has been a weak acid that has been dissociated into the constituent ions. The dissociation of the compound in water has been corresponds to the equilibrium constant.
The equilibrium constant has been defined as the ratio of the concentration of solute and solvent ions at equilibrium.
The sample with lesser equilibrium constant tends to dissociate at lesser concentration as well.
The equilibrium constant for the dissociation of hydrogen cyanide has been smaller than HCl. Thus, there will be lesser dissociation of hydrogen cyanide as compared to HCl. Hence, option C is correct.
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