Q9 of 27 Page 1

(a) Actinoid contraction is greater than lanthanoid contraction. Give reason.

(b) Out of Fe and Cu, which has higher melting point and why?


(a) From element to element actinoid contraction is greater than lanthanoid contraction because the 5f electrons provide very poor shielding effect.


(b) Fe has higher melting point than Cu. Since, the melting point depends on the no. of metallic bonds which are formed by the unpaired electrons of the metal atoms. As Fe has more no. of unpaired electrons as compared to Cu thus its melting point will also be high.


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7

For a reaction, C2H4 (g) + H2(g) → C2H6(g), rate = 5.5 10-14 [C2H4].

(a) Write the unit of rate constant.


(b) Calculate its half-life (t1/2).


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(a) Draw the structure of an oxide of nitrogen where the oxidation state of nitrogen is +5.

(b) With the help of a balanced chemical equation, suggest what happens when white phosphorus reacts with NaOH solution in an inert atmosphere.


 10

Predict the major product obtained when t-butyl bromide reacts with sodium methoxide. Also, give its IUPAC name.

OR


(a) Show the chemical reaction with bond movements and arrows for the nucleophilic attack of water on carbocation in acid catalysed hydration of alkenes.


(b) Give IUPAC name for the following:



 11

Aluminium crystallises in a fcc structure. Atomic radius of the metal is 125 pm. What is the length of the side of unit cell of the metal?

OR


The compound CuCl has fcc structure like ZnS. Its density is 3.04 g cm-3. What is the volume of unit cell? Given: Atomic mass of Cu = 63.5 u; Cl = 35.5 u NA = 6.02 1023 mol-1.