NEET Questions Solved


Which acts as inhibitor for knocking in combustion of petrol?

(a) (C2H5)4Pb                     (b) Ni(CO)4

(c) both (a) and (b)              (d) none of these

(c) Both are antiknock compounds.

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Negative catalyst or inhibitor is one:

(a) which retards the rate of reaction

(b) takes the reaction in forward direction

(c) promotes the side reaction

(d) none of the above

(a) The definition of negative catalyst.

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When a catalyst is added to a system the:

(a) equilibrium concentrations are increased

(b)equilibrium concentrations are unchanged

(c) the rate of forward reaction is increased and that of backward reaction is decreases

(d)value of equilibrium constant is decreased

(b) Catalyst never changes the equilibrium constant

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Which acts as a promoter for nickel in the hydrogenation of oils ?

(a) Cu

(b) Mo

(c) Fe

(d) Pt

(a) Cu acts as promoter for Ni.

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In Zeigler-Natta polymerisation of ethylene, the active species is:

(1)AlCl3

(2)Et3Al

(3)CH2CH2

(4)TiIII

 

 

 

 

(a)Zeigler-Natta catalyst is formed by the action of (C2H5)3Al and TiCl4. the active species is (C2H5)3Al  can reduce TiCl4 to TiCl3. TiIII has one active site vacant and thus accommodates one alkyl group

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The decomposition of H2O2 may be checked by adding a small quantity of phosphoric acid. This is an example of:

(a) neutralization                              (b) negative catalysis

(c) positive catalysis                         (d) catalytic poisoning

(b) H3PO4, acetamide acts as negative catalyst for decomposition of H2O2.

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Pd can absorb 900 times its volume of hydrogen. This called:

(a) absorption

(b)adsorption

(c)occlusion

(d) both (b) and(c)

(d) Adsorption and occlusion have same meaning.

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Which acts as poison for Pd-charcoal in lindlar's catalyst ?

(a) BaSO4

(b) Quiniline

(c) Both (a) and (b)

(d) None of these

(c) Either BaSO4 or Quiniline are used to used the activity of Pd-charcoal. The catalyst Pd-charcoal/BaSO4 or Quiniline is used to hydrogenate alkyne to alkene only

CHCH+H2Lindlar's catalystCH2=CH2

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Platinized asbestos used as a catalyst in the manufacture of H2SO4 is an example of:

(a) heterogeneous catalyst                    (b) auto-catalyst

(c) homo-catalyst                                 (d) induced catalyst

(a) SO2(g) + (1/2)O2(g)Pt(s)SO3(g)

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In a reversible reaction, a catalyst:

(a) increases the rate of the forward reaction only

(b) increases the rate of the forward reaction to a greater extent than that of  the backward reaction

(c) increases the rate of the forward reaction and decreases that of the backward reaction to the different extent

(d) increases the rate of the forward and backward reactions equally

(d) An increase in rate of reaction in forward direction by a catalyst for a reaction in equilibrium brings in an increase in concentration of products and thus, rate of backward reaction also increases to same magnitude and the equilibrium position is not altered.

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