Short Answer TypeAn element with molar mass 27 g mol-1 forms a cubic unit cell with edge length 4.05 x 10-8 cm . If its density is 2.7 g cm-3 , what is the nature of the cubic unit cell?
How would you account for the following?
Actinoid contraction is greater than lanthanoid contraction.
For a reaction A + B → P, the rate is given by Rate = k[A] [B]2
(i) How is the rate of reaction affected if the concentration of B is doubled?
(ii) What is the overall order of reaction if A is present in large excess?
A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
(log 2 = 0.3010)
Account for the following:
(i) Acidic character increases from HF to HI.
(ii) There is a large difference between the melting and boiling points of oxygen and sulphur.
(iii) Nitrogen does not form pentahalide.
Which would undergo SN2 reaction faster in the following pair and why?
Sn2 reactions are bimolecular with simultaneous bond-making and bond-breaking steps. Primary alkyl halides prefer to undergo SN2 reactions than tertiary alkyl halides because of less steric hindrance experienced by the approaching nucleophile.
Hence, out of the given pair, (CH3 –CH 2 – Br ) would undergo SN2 reaction faster.
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