For a metal ion,the calculated magnetic moment is $4.90 \ BM$. This metal ion has $........$ number of unpaired electrons.

Total number of stereoisomers of $[Co(acac)_2BrCl]^{\ominus}$ are

$CoSO_{4}Cl \cdot 5NH_{3}$ exists in two isomeric forms '$A$' and '$B$'. Isomer '$A$' reacts with $AgNO_{3}$ to give white precipitate,but does not react with $BaCl_{2}$. Isomer '$B$' gives white precipitate with $BaCl_{2}$ but does not react with $AgNO_{3}$. Answer the following questions.
$(i)$ Identify '$A$' and '$B$' and write their structural formulas.
$(ii)$ Name the type of isomerism involved.
$(iii)$ Give the $IUPAC$ name of '$A$' and '$B$.'

How many optical isomers are possible for the complex $[Pt(NH_3)_2(CN)_2]$?

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$a. [Fe(CN)_{6}]^{3-}$	$i. 5.92 \ BM$
$b. [Fe(H_{2}O)_{6}]^{3+}$	$ii. 0 \ BM$
$c. [Fe(CN)_{6}]^{4-}$	$iii. 4.90 \ BM$
$d. [Fe(H_{2}O)_{6}]^{2+}$	$iv. 1.73 \ BM$

Choose the correct answer from the options given below.

Atomic numbers of $Cr$ and $Fe$ are $24$ and $26$ respectively. Which of the following is paramagnetic?