$A$. $Al^{3+}$ $B$. $Cu^{2+}$ $C$. $Ba^{2+}$ $D$. $Co^{2+}$ $E$. $Mg^{2+}$
નીચે આપેલા વિકલ્પોમાંથી સાચો જવાબ પસંદ કરો.
| Group | Cations |
| Group $-II$ | $\mathrm{Cu}^{2+}$ |
| Group $-III$ | $\mathrm{Al}^{3+}$ |
| Group $-IV$ | $\mathrm{Co}^{2+}$ |
| Group $-V$ | $\mathrm{Ba}^{2+}$ |
| Group $-VI$ | $\mathrm{Mg}^{2+}$ |
The correct order of group number of ions is $\underset{\text { (B) }}{\mathrm{Cu}^{2+}} < \underset{\text { (A) }}{\mathrm{Al}^{3+}} < \underset{\text { (D) }}{\mathrm{Co}^{2+}} < \underset{\text { (C) }}{\mathrm{Ba}^{2+}} < \underset{\text { (E) }}{\mathrm{Mg}^{2+}}$
$\therefore$ The correct order is $\mathrm{B}, \mathrm{A}, \mathrm{D}, \mathrm{C}, \mathrm{E}$
(આપેલ : પરમાણુક્રમાંક $\mathrm{Sc}=21, \mathrm{Ti}_{\mathrm{i}}=22, \mathrm{~V}=23, \mathrm{Cr}=24, \mathrm{Mn}=25$ અને $\mathrm{Zn}=30$ )
$(I)$ ગલન બિંદુ $(II)$ ઉત્કલન બિંદુ $(III)$ ઘનતા