NEET Chemistry The p-Block Elements (XI) Questions Solved


Which loses weight on exposure to the atmosphere ?

(a) Concentrated H2SO4

(b) Solid NaOH

(c) A saturated solution of CO2

(d) Anhydrous sodium carbonate

(c) CO2 escapes out slowly.

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Which of the following compound is weakest Lewis acid ?

(1) BF3

(2) BCl3

(3) BBr3

(4) BI3

(1) Extent of back bonding decreases from BF3 to BI3. So, lewis acidic character increases from BF3 to BI3. Hence, BF3 is the weakest lewis acid.

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Which does not show inert pair effect

(1) Al

(2) Sn

(3) Pb

(4) Thallium

(1) Al does not show inert pair effect due to unavailability of d subshell.

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Pick the correct statement :

(1) Borax is white crystalline solid containing [B4O5(OH)4]2- units

(2) Aqueous solution of borax is acidic in nature.

(3) Cobalt gives green colour in borax bead test.

(4) All are incorrect.

(1) Borax is white crystalline solid containing [B4O5(OH)4]2- units.

Aqueous solution of borax is alkaline in nature. Cobalt gives blue colour borax bead test. 

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Mark the oxide which is amphoteric in character

(1) CO2

(2) CO

(3) SnO2

(4) CaO

(3)

CO2 - acidic,

CO - neutral,

SnO2 - amphoteric,

CaO - basic

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In B2H6 

(1) there is direct boron-boron bond

(2) the structure is similar to that of C2H6

(3) the boron atoms are linked through hydrogen bridges

(4) all the atoms are in one plane

(3) Fact

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H3BO3 is

(1) monobasic and weak Lewis acid

(2) monobasic and weak bronsted acid

(3) monobasic and strong Lewis acid

(4) tribasic and weak Bronsted acid

(1) H3BO3 is not a protonic acid. It can accept one OH- and converted into [B(OH)4]-. So, it is a weak monobasic lewis acid.

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From the B2H6 all the following can be prepared except:

(1) H3BO3

(2) [BH2(NH3)2]+ [BH4]-

(3) B2(CH3)6

(4) NaBH4

(1) Fact

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Which of the following shows correct Lewis acidic strength order of trihalides of boron ?

(1) BCl3 > BBr3 > BF3 > BI3

(2) BF3 < BBr3 < BCl3 < BI3

(3) BF3 < BCl3 < BBr3 < BI3

(4) BF3 >BCl3 > BBr3 > BI3

(3) Extent of back bonding decreases from BF3 to BI3.

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The correct order of ease of hydrolysis is 

(1) CCl4 < SiCl4 < PCl5 < AlCl3

(2) AlCl3 < CCl4 < PCl5 < SiCl4

(3) CCl4 < AlCl3 < PCl5 < SiCl4

(4) CCl4 < AlCl3 < SiCl4 < PCl5

(4) Fact

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