94420 + Interview Questions in Chemistry in Class 12

1.	Libermannreactionis givenonlyby :
Answer» PRIMARY amine SECONDARY amine Tetiary amine NONE of these Answer :B

Discussion

2.	Libermann's test used for identification of which functional group in organic compounds
Answer» ALCOHOL `1^(0)` - amine Phenolic aldehyde Answer :C

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3.	Liberation of iodine which gives a …………….colouration with starch.
Answer» SOLUTION :BLUE - BLACK

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4.	_____liberates oxygen from water.
Answer» P Na `F_2` `I_2` ANSWER :C

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5.	LiAlH_(4)andNaBH_(4) are
Answer» `H^(+)` DONOR `H^(-)` donor `H^(-)` acceptor None Answer :B

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6.	LiAlH_4is a best reagent to prepare unsaturated alcohol. Prove it.
Answer» Solution :`LiAlH_4` (LITHIUM Aluminium HYDRIDE) does not reduce the carbon-carbondouble BOND present in the carbonyl compound and hence it is the BEST reagent to prepare UNSATURATED alcohol. `underset(("Prop - 2- enal"))underset("Crotanaldehyde")(CH_3-CH=CH-CHO)underset(H_2O)overset(LiAlH_4)tounderset(("but-2-en-1-ol"))underset("Crotyl alcohol")(CH_3-CH = CH - CH_2OH)`

Discussion

7.	LiAlH_(4) is a best reagent to prepare unsaturated alcohol. Prove it.
Answer» Solution :`LiAlH_(4)` (Lithium Aluminium Hydride) does not reduce the carbon - carbon double bond present in the CARBONYL compound and hence it is the best reagent to prepare unsaturated alcohol. `underset("(PROP -2- enal)")underset("Crotanaldehyde")(CH_(3)-CH=CH-CHO)overset(LiAlH_(4))underset(H_(2)O)rarrunderset("(but -2- EN -1- ol)")underset("Crotyl alcohol")(CH_(3)-CH=CH-CH_(2)OH)`

Discussion

8.	LiAlH_4 is used as :
Answer» An OXIDISING agent A REDUCING agent A mordant A WATER softener Answer :B

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9.	LiAlH_(4) converts acetic acid into-
Answer» Acetaldehyde Methane Ethyl alcohol Methyl alcohol Solution :`CH_(3)COOH + 4H OVERSET(LiAIH_(4))to CH_(3)CH_(2)OH + H_(2)O`

Discussion

10.	LiAIH_4 is used as :
Answer» OXIDISING agent Reducing agent A mordant Water softner Answer :B

Discussion

11.	Li occupies higher position in the electrochemical series of metals as compared to Cu since
Answer» the standard REDUCTION POTENTIAL `Li^+`/Li is lower than that of `CU^(2+)`/Cu the standard reduction potential of `Cu^(2+)` /Cu is lower than that of `Li^(2+)`/Li the standard oxidation potential of `Li^(2+)`/LIT is lower than that of `Cu//Cu^(2+)` Li is sinaller in size as compared to Cu. Solution : the standard reduction potential `Li^+`/Li is lower than that of `Cu^(2+)`/Cu

Discussion

12.	Li occupies higher position in the electrochemical series of metal as compared to Cu, since
Answer» the STANDARD reduction POTENTIAL of `Li^(+)//Li` is lower than that of `Cu^(2+)//Cu`. the standard reduction potential of `Cu^(2+)//Cu` is lower than that of `Li^(+)//Li` the standard oxidation potential of `Li//Li^(+)` is lower than that of `Cu//Cu^(2+)` Li is SMALLER in size as COMPARED to Cu. Answer :A

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13.	Li and Mg both combine with N_(2) at high temp. This suggest that the two metalshave
Answer» HORIZONTAL RELATIONSHIP vertical relationship diagonal relationship no relationship ANSWER :C

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14.	Lewis -structure SO_(4)^(2-)
Answer»

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15.	The reaction quotient ‘Q.’ is useful in predicting the direction of the reaction. Which of the following is incorrect?
Answer» If `Q_(C) GT K_(c)` , the reverse reaction is favoured If`Q_(C) lt K_(c)` the forward reaction is favoured. If`Q_(C) gt K_(c)`forward reaction is favoured. If `Q_(c) = K_(c)`, no reaction occur. Solution :(a) If `Q_(c) gt K_(c)`, the reaction will proceed from RIGHT to left i.e., reverse reaction is favoured. (b) If `Q_(c) lt K_(c)` the reaction will proceed from left to right i.e., forward reaction is favoured. (d) If `Q_(c) = K_(c)` the reaction is ALREADY at equilibrium and no reaction occurs.

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16.	Lewis -structure SO_(3)
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17.	Lewis -structure SO_(2)
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18.	Lewis -structure SiF_(4)
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19.	Lewis -structure SnCl_(3)^(-)
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20.	Lewis -structure SCN^(-)
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21.	Lewis -structure PO_(3)^(-3)
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22.	Lewis -structure OCN^(-)
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23.	Lewis -structure O_(3)
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24.	Lewis -structure NOCl
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25.	Lewis -structure NO_(3)^(-)
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26.	Lewis -structure NO_(2)Cl
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27.	Lewis -structure NO_(2)^(-)
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28.	Lewis -structure NH_(4)^(+)
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29.	Lewis -structure N_(3)^(-)
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30.	Lewis -structure NH_(2)Cl
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31.	Lewis -structure HNC
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32.	Lewis -structure HCN
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33.	Lewis -structure H_(3)O^(+)
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34.	Lewis -structure F_(2)O
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35.	Lewis -structure COCl_(2)
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36.	Lewis -structure CO_(2)
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37.	Lewis -structure CO_(3)^(2-)
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38.	Lewis -structure CN^(-)
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39.	Lewis -structure CO
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40.	Lewis -structureCH_(3)Cl
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41.	Lewis -structure C Cl_(3)
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42.	Lewis -structure BH_(4)^(-)
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43.	Lewis -structure BeF_(4)^(2-)
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44.	Lewis concept of ccovalency of an element involved octet rule. Later on it was found that may elements in their compounds e.g. BeF_(2),BF_(3) etc, have incomplete octet whereas PCl_(5), SF_(6) etcc. Have expanded octet. This classical concept also failed in predicting the geometry of molecules. Modern concept of covalence was proposed in terms of valence bond theory. Hybridization concept along with v.B. Theory successfully molecules was explained by VSEPR concept. Finally molecular orbital theory was proposed to explain many other molecules. Which statements are correct for CO^(+) and N_(2)^(-) according to M.O. Theory: (I) Both have same configuration. (II) Bond order for CO^(+) and N_(2)^(+) are 3.5 and 2.5 (III) Bond order of CO^(+) and N_(2)^(+) are same. (IV) During the formation of N_(2)^(@) from N_(2) bond length increases. (V) During the formation of CO^(+) from CO, the bond length decreases.
Answer» II, IV, V I, III, IV,V I,III I,II,III Answer :A

Discussion

45.	Lewis -structure BF_(4)^(-)
Answer»

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46.	Lewis concept of ccovalency of an element involved octet rule. Later on it was found that may elements in their compounds e.g. BeF_(2),BF_(3) etc, have incomplete octet whereas PCl_(5), SF_(6) etcc. Have expanded octet. This classical concept also failed in predicting the geometry of molecules. Modern concept of covalence was proposed in terms of valence bond theory. Hybridization concept along with v.B. Theory successfully molecules was explained by VSEPR concept. Finally molecular orbital theory was proposed to explain many other molecules. Which are true statements among the following? (i) I_(3)^(+) has bent structure. (ii) P_(pi) - P_(pi) bonds are present in SO_(2). (III) SeF_(4) and CH_(4) has same shape. (IV) XeF_(2) andd CO_(2) has same shape. (V) SF_(4) is sea-saw structure whereas ICl_(3) is T-shaped.
Answer» I,II,IV,V I,II,III,IV II,III,IV,V I,III,IV,V Solution :`SeF_(4)` is SEA -saw shaped whereas `CH_(4)` is tetrahedral.

Discussion

47.	Lewis concept of ccovalency of an element involved octet rule. Later on it was found that may elements in their compounds e.g. BeF_(2),BF_(3) etc, have incomplete octet whereas PCl_(5), SF_(6) etcc. Have expanded octet. This classical concept also failed in predicting the geometry of molecules. Modern concept of covalence was proposed in terms of valence bond theory. Hybridization concept along with v.B. Theory successfully molecules was explained by VSEPR concept. Finally molecular orbital theory was proposed to explain many other molecules. The bond angles NO_(2)^(+), NO_(2) and NO_(2)^(-) are respectively.
Answer» `180^(@), 134^(@), 115^(@)` `115^(@), 134^(@), 180^(@)` `134^(@), 180^(@), 115^(@)` `115^(@), 180^(@), 130^(@)` Solution :Greater the no. of LONE pair on N-atom, SMALLER will be the bond angle.

Discussion

48.	Lewis base is
Answer» `CO_(2)` `SO_(3)` `SO_(2)` ROH Solution :ROH is a LEWIS base because it has an lone pair of ELECTRON.

Discussion

49.	Lewis acids are
Answer» ELECTRON ACCEPTORS PROTON acceptors electron donors proton donors Answer :A

Discussion

50.	Lewis acid character of boron trihalides is as a follows :
Answer» `BF_(3) GT BCl_(3) gt BBr_(3) gt BI_(3)` `BCl_(3)gt BF_(3) gt BBr_(3)gt BI_(3)` `BI_(3)gt BBr_(3)gt BCl_(3)gt BF_(3)` `BI_(3) gt BF_(3)gt BCl_(3) gt BBr_(3)` Answer :C

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Libermannreactionis givenonlyby :

Libermann's test used for identification of which functional group in organic compounds

Liberation of iodine which gives a …………….colouration with starch.

_____liberates oxygen from water.

LiAlH_(4)andNaBH_(4) are

LiAlH_4is a best reagent to prepare unsaturated alcohol. Prove it.

LiAlH_(4) is a best reagent to prepare unsaturated alcohol. Prove it.

LiAlH_4 is used as :

LiAlH_(4) converts acetic acid into-

LiAIH_4 is used as :

Li occupies higher position in the electrochemical series of metals as compared to Cu since

Li occupies higher position in the electrochemical series of metal as compared to Cu, since

Li and Mg both combine with N_(2) at high temp. This suggest that the two metalshave

Lewis -structure SO_(4)^(2-)

The reaction quotient ‘Q.’ is useful in predicting the direction of the reaction. Which of the following is incorrect?

Lewis -structure SO_(3)

Lewis -structure SO_(2)

Lewis -structure SiF_(4)

Lewis -structure SnCl_(3)^(-)

Lewis -structure SCN^(-)

Lewis -structure PO_(3)^(-3)

Lewis -structure OCN^(-)

Lewis -structure O_(3)

Lewis -structure NOCl

Lewis -structure NO_(3)^(-)

Lewis -structure NO_(2)Cl

Lewis -structure NO_(2)^(-)

Lewis -structure NH_(4)^(+)

Lewis -structure N_(3)^(-)

Lewis -structure NH_(2)Cl

Lewis -structure HNC

Lewis -structure HCN

Lewis -structure H_(3)O^(+)

Lewis -structure F_(2)O

Lewis -structure COCl_(2)

Lewis -structure CO_(2)

Lewis -structure CO_(3)^(2-)

Lewis -structure CN^(-)

Lewis -structure CO

Lewis -structureCH_(3)Cl

Lewis -structure C Cl_(3)

Lewis -structure BH_(4)^(-)

Lewis -structure BeF_(4)^(2-)

Lewis -structure BF_(4)^(-)

Lewis base is

Lewis acids are

Lewis acid character of boron trihalides is as a follows :