Explanation

(b)
Propanal is not formed during the dry distillation of a mixture of calcium formate and calcium acetate.
$(HCOO)_{2}Ca\ \overset{\ \ Dry\ distilllation\ \ \ }{\rightarrow}HCHO + CaCO_{3}$
$\left( CH_{3}COO \right)_{2}Ca\overset{\ \ \ \ \ \mathrm{\Delta}\ \ \ \ \ }{\rightarrow}CH_{3}COCH_{3} + \ CaCO_{3}$
$(HCOO)_{2}Ca + \left( CH_{3}COO \right)_{2}Ca\overset{\ \ \ \ \mathrm{\Delta}\ \ \ \ \ \ }{\rightarrow}2CH_{3}CHO + 2CaCO_{3}$