The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature

What are $\underline{A}, \underline{B}, \underline{C}$ in the following reactions?
$(I)$ $(CH_3 CO_2)_2 Ca \xrightarrow{\Delta} \underline{A}$
$(II)$ $CH_3 CO_2 H \xrightarrow[Red\ P]{HI} \underline{B}$
$(III)$ $2 CH_3 CO_2 H \xrightarrow{P_4 O_{10}} \underline{C}$
$\underline{A} \quad \underline{B} \quad \underline{C}$

Which of the following is an amphoteric hydroxide?

Consider the following statements regarding Werner's theory of coordination compounds:
$(1)$ Ligands are connected to the metal ions by coordinate bonds (dative bonds).
$(2)$ Secondary valencies have directional properties.
$(3)$ Secondary valencies are non-ionisable.
Which of these statements are correct?

Which animal possesses neurons but lacks a brain?

In the circuit element given here,if the potential at point $B$,$V_B = 0$,then the potentials of $A$ and $D$ are given as