Problem 142
Which ion can show different colours in different compounds? (a) \(\mathrm{Sr}^{2+}\) (b) \(\mathrm{Ni}^{2+}\) (c) \(\mathrm{Pb}^{2+}\) (d) \(\mathrm{Cd}^{2+}\)
Problem 143
If \(\mathrm{Pb}\left[\mathrm{CH}_{3} \mathrm{COO}\right]_{2}\) and \(\mathrm{Na}_{2} \mathrm{~S}\) are mixed and dissolved in water and the solution is filtered then the filtrate will give test of (a) \(\mathrm{CH}_{3} \mathrm{COO}^{-}\) (b) \(\mathrm{Pb}^{2+}\) (c) \(\mathrm{Na}^{+}\) (d) \(\mathrm{S}^{2-}\)
Problem 145
\(\mathrm{FeCl}_{3}\) is acidic towards litmus. On treatment with excess of \(\mathrm{NH}_{4} \mathrm{SCN}\) it gives red coloured compound (A) and on treatment with excess of \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) in the presence of conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), it evolves deep red vapours of on passing the vapours of (B) into \(\mathrm{NaOH}\), then adding a solution of acetic acid and lead acetate it gives yellow precipitate of compound of chromium (C). The compound (B) is (a) \(\mathrm{CrO}_{2} \mathrm{Cl}_{2}\) (b) \(\mathrm{Br}_{2}\) (c) \(\mathrm{NO}_{2}\) (d) \(\mathrm{CrOCl}_{4}\)
Problem 146
\(\mathrm{FeCl}_{3}\) is acidic towards litmus. On treatment with excess of \(\mathrm{NH}_{4} \mathrm{SCN}\) it gives red coloured compound (A) and on treatment with excess of \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) in the presence of conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\), it evolves deep red vapours of on passing the vapours of (B) into \(\mathrm{NaOH}\), then adding a solution of acetic acid and lead acetate it gives yellow precipitate of compound of chromium (C). The compound (A) is (a) \(\mathrm{NH}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{4}\right]\) (b) \(\mathrm{Fe}(\mathrm{SCN})_{2}\) (c) \(\mathrm{FeCl}_{3}\) (d) \(\mathrm{Fe}(\mathrm{SCN})_{3}\)
Problem 147
Borax \(\left[\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} .10 \mathrm{H}_{2} \mathrm{O}\right]\) when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. $$ \begin{array}{ll} \text { Colour of the bead } & \text { Ion } \\ \text { Blue green or light blue } & \mathrm{Cu}^{2+} \\ \text { Yellow } & \mathrm{Fe}^{2+} \text { or } \mathrm{Fe}^{3+} \\ \text { Green } & \mathrm{Cr}^{3+} \\ \text { Violet } & \mathrm{Mn}^{2+} \\ \text { Dark blue } & \mathrm{Co}^{2+} \\ \text { Brown } & \mathrm{Ni}^{2+} \end{array} $$ The hybridisation of \(\mathrm{B}\) in borax is (a) sp (b) \(\mathrm{sp}^{2}\) (c) \(\mathrm{sp}^{3}\) (d) Both (B) and (C)
Problem 148
Borax \(\left[\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} .10 \mathrm{H}_{2} \mathrm{O}\right]\) when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. $$ \begin{array}{ll} \text { Colour of the bead } & \text { Ion } \\ \text { Blue green or light blue } & \mathrm{Cu}^{2+} \\ \text { Yellow } & \mathrm{Fe}^{2+} \text { or } \mathrm{Fe}^{3+} \\ \text { Green } & \mathrm{Cr}^{3+} \\ \text { Violet } & \mathrm{Mn}^{2+} \\ \text { Dark blue } & \mathrm{Co}^{2+} \\ \text { Brown } & \mathrm{Ni}^{2+} \end{array} $$ Glassy bead is of (a) \(\mathrm{Na}_{3} \mathrm{BO}_{3}\) (b) \(\mathrm{B}_{2} \mathrm{O}_{3}+\mathrm{NaBO}_{2}\) (c) \(\mathrm{SiO}_{2}\) (d) \(\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7}\)
Problem 149
Borax \(\left[\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} .10 \mathrm{H}_{2} \mathrm{O}\right]\) when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. $$ \begin{array}{ll} \text { Colour of the bead } & \text { Ion } \\ \text { Blue green or light blue } & \mathrm{Cu}^{2+} \\ \text { Yellow } & \mathrm{Fe}^{2+} \text { or } \mathrm{Fe}^{3+} \\ \text { Green } & \mathrm{Cr}^{3+} \\ \text { Violet } & \mathrm{Mn}^{2+} \\ \text { Dark blue } & \mathrm{Co}^{2+} \\ \text { Brown } & \mathrm{Ni}^{2+} \end{array} $$ The colour of bead \(\mathrm{Ni}\left(\mathrm{BO}_{2}\right)_{2}\) is of (a) Brown (b) Blue (c) Green (d) Violet
Problem 150
Borax \(\left[\mathrm{Na}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} .10 \mathrm{H}_{2} \mathrm{O}\right]\) when heated on platinum loop it gives a dark transparent glass like bead. The hot bead is dipped in the salt till it reacts with transition metal oxide. It produces characteristic bead of meta borate. $$ \begin{array}{ll} \text { Colour of the bead } & \text { Ion } \\ \text { Blue green or light blue } & \mathrm{Cu}^{2+} \\ \text { Yellow } & \mathrm{Fe}^{2+} \text { or } \mathrm{Fe}^{3+} \\ \text { Green } & \mathrm{Cr}^{3+} \\ \text { Violet } & \mathrm{Mn}^{2+} \\ \text { Dark blue } & \mathrm{Co}^{2+} \\ \text { Brown } & \mathrm{Ni}^{2+} \end{array} $$ The flame used in borax bead test is (a) Oxidising (b) Reducing (c) Both (A) and (B) (d) Neither (A) nor (B)
Problem 151
Match the following $$ \begin{array}{ll} \hline \text { List-I } & \text { List-II } \\ \hline \text { a. } \mathrm{AgNO}_{3}+\mathrm{NaCNS} & \text { (p) White } \\ \text { b. } \mathrm{AgNO}_{3}+\mathrm{Na}_{3} \mathrm{PO}_{4} & \text { (q) Black } \\ \text { c. } \mathrm{AgNO}_{3}+\mathrm{K}_{2} \mathrm{CrO}_{4} & \text { (r) Brick red } \\ \text { d. } \mathrm{AgNO}_{3}+\mathrm{Na}_{2} \mathrm{~S} & \text { (s) Yellow } \\ \hline \end{array} $$
Problem 152
Match the following $$ \begin{array}{ll} \text { List-I } & \text { List-II } \\ \hline \text { a. } \operatorname{Borax} \stackrel{\Delta}{\longrightarrow} & \text { (p) } \mathrm{BN} \\ \text { b. } \text { Borax }+\mathrm{NH}_{4} \mathrm{Cl} \stackrel{\Delta}{\longrightarrow} & \text { (q) } \mathrm{H}_{2} \mathrm{~B}_{4} \mathrm{O}_{7} \end{array} $$ c. Borax \(\stackrel{\Delta}{\longrightarrow}\) (r) \(\mathrm{H}_{3} \mathrm{BO}_{3}\) d. Borax \(+\mathrm{H}_{2} \mathrm{O} \longrightarrow\) (s) \(\mathrm{NaBO}_{2}+\mathrm{B}_{2} \mathrm{O}_{3}\)
