The pair$(s)$ of diamagnetic ions is$(are)$
$(A) \ La ^{3+}, Ce ^{4+}$ $(B) \ Yb ^{2+}, Lu ^{3+}$ $(C) \ La ^{2+}, Ce ^{3+}$ $(D) \ Yb ^{3+}, Lu ^{2+}$

Observe the following reaction: $2A + B \longrightarrow C$. The rate of formation of $C$ is $2.2 \times 10^{-3} \ mol \ L^{-1} \ min^{-1}$. What is the value of $-\frac{d[A]}{dt}$ (in $mol \ L^{-1} \ min^{-1}$)?

The monomers used in the production of nylon-$6,6$ are

How many bridging oxygen atoms are present in $P_4O_{10}$?

The major product of the following reaction is

Which sample contains a greater number of nuclei: a $5.00 \, \mu Ci$ sample of $^{240}Pu$ (half-life $6560 \, y$) or a $4.45 \, \mu Ci$ sample of $^{243}Am$ (half-life $7370 \, y$)?