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ICSE Class 10 Chemistry Question 6 of 18

Solved 2019 Question Paper ICSE Class 10 Chemistry — Question 12

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12
Question

Question 1(h)

Arrange the following according to the instructions given in brackets:

(i) K, Pb, Ca, Zn. (In the increasing order of the reactivity)

(ii) Mg2+, Cu2+, Na1+, H1+ (In the order of preferential discharge at the cathode)

(iii) Li, K, Na, H (In the decreasing order of their ionization potential)

(iv) F, B, N, O (In the increasing order of electron affinity)

(v) Ethane, methane, ethene, ethyne. (In the increasing order of the molecular weight) [H = 1, C = 12]

Answer

(i) Pb < Zn < Ca < K

(ii) Cu2+, H1+, Mg2+, Na1+

Lower the position of the ion, greater the tendency to be liberated at the cathode (or respective electrode).

(iii) H > Li > Na > K

Ionization Potential decreases as we move down the group.

(iv) B < N < O < F

Electron Affinity increases from left to right across a period.

(v) Methane < Ethyne < Ethene < Ethane

Ethane [C2H6] : M.W. = 2[12] + 6[1] = 30

Methane [CH4] : M.W. = 12 + 4[1] = 16

Ethene [C2H4] : M.W. = 2[12] + 4[1] = 28

Ethyne [C2H2] : M.W. = 2[12] + 2[1] = 26

Hence, increasing order of molecular weight : Methane < Ethyne < Ethene < Ethane