What is $Z$ in the following reaction? $CH_3-CH_2-CO_2^{\ominus} Na^{\oplus} \stackrel{NaOH / CaO}{\longrightarrow} Z$

The number of ways of arranging $8$ men and $4$ women around a circular table such that no two women can sit together is

Power delivered by the $ac$ source of the circuit becomes maximum when

Dry distillation of calcium acetate and calcium formate forms:

Four rods of the same material and having the same cross-section and length have been joined as shown in the figure. The temperature of the junction of the four rods will be . . . . . . $^oC$.

During which phase of mitosis do the nuclear envelope and nucleolus completely disappear?