31.Among $ [Fe(H_{2}O)_{6}]^{3+},[Fe(CN)_{6}]^{3-},[Fe(Cl)_{6}]^{3-}$ species, the hybridisation state of the Fe atom are respectively A) $d^{2}sp^{3},d^{2}sp^{3},sp^{3}d^{2}$ B) $sp^{3}d^{2},d^{2}sp^{3},d^{2}sp^{3}$ C) $sp^{3}d^{2},d^{2}sp^{3},sp^{3}d^{2}$ D) none of the above View Answer Report DiscussAnswer: Option CExplanation:
32.A metal has bcc structure and the edge length of its unit cell is 3.04Å .The volume of the unit cell in $cm^{3}$ will be A) $1.6 \times10^{21}cm^{3}$ B) $2.81 \times10^{-23}cm^{3}$ C) $6.02 \times10^{-23}cm^{3}$ D) $6.6 \times10^{-24}cm^{3}$ View Answer Report DiscussAnswer: Option BExplanation:Volume of unit cell (V)=$a^{3}$ $\therefore$ =$(3.04 \times 10^{-8}cm)^{3}$ =$2.81 \times 10^{-23} cm^{3}$
33.$MnO_{4}^{-}+8H^{+}+5e^{-} \rightarrow Mn^{2+}+4H_{2}O;$ $E^{0}=1.51V$ $MnO_{2}+4H^{+}+2e^{-} \rightarrow Mn^{2+}+2H_{2}O$; $E^{0}=1.23 VE^{0}_{MnO_{4}^{-}| MnO_{2}}$ is A) 1.70 V B) 0.91 V C) 1.37 V D) 0.548V View Answer Report DiscussAnswer: Option AExplanation: On subtracting eqn.(ii) from (i) we get $MnO_{4}^{-}+4H^{+}+3e^{-} \rightarrow MnO_{2}+2H_{2}O$ $\therefore$ $-E_{3}= \frac{-1.51 \times 5+2 \times 1.23}{3}$ $\therefore$ $E_{3}=1.70V$
34.The volume strength of 1.5 $NH_{2}0_{2}$ solution is A) 16.8L B) 8.4L C) 4.2L D) 5.2L View Answer Report DiscussAnswer: Option BExplanation:Volume strength =$5.6 \times$ normality $=5.6 \times 1.5$ =8.4 L
35. The sodium extract of an organic compound on acidification with acetic acid and addition of lead acetate solution gives a black precipitate. The organic compound contains A) nitrogen B) halogen C) sulphur D) phosphorus View Answer Report DiscussAnswer: Option CExplanation:The organic compounds containing sulphur when reacting with sodium metal give $Na_{2}S$. The $Na_{2}S$ when reacting with lead acetate forms black ppt.of PbS $Na_{2}S+(CH_{3}COO)_{2}Pb \rightarrow PbS+2CH_{3}COONa$ Black ppt.
