Short Answer TypeGive reasons for the following:
(i) N2 is less reactive at room temperature.
(ii) H2Te is the strongest reducing agent amongst all the hydrides of Group 16 elements.
(iii) Helium is used in diving apparatus as a diluent for oxygen.
Two nitrogen atoms are joined by triple bonds. The nitrogen atom is very small, therefore the bond length is also quite small (109.8pm) and as the result, the bond dissociation energy is quite high (946Kj/mol) Therefore, N2 is less reactive at room temperature.
H2Te is the strongest reducing agent among the hydrides of group 16. The size of Te is very large due to which the bonding between hydrogen and Te is not strong. On the other hand, the electronegativity of Te is very less. So it will easily loose hydrogen. As the size of the elements increases in the order O < S < Se < Te, thus bond strength decreases from H2O to H2Te and therefore, the bond dissociation enthalpy decreases. Hence, due to the increase in the tendency to release proton, the element's reducing tendency also increases.
(iii) Helium is used in diving apparatus as a diluent for oxygen because it is chemically inert and does not participate in the chemical reaction. Helium has low solubility in water than many other gases, such as nitrogen. Due to low solubility means it does not enter the bloodstream, even under pressure commonly experienced by deep sea divers.
(a) Write the hybridization and shape of the following complexes:
(i) [CoF6]3–
(ii) [Ni (CN)4]2–
(Atomic number: Co = 27, Ni = 28)
(b) Out of NH3 and CO, which ligand forms a more stable complex with a transition metal and why?
Calculate the freezing point of the solution when 31 g of ethylene glycol (C2H6O2) is dissolved in 500 g of water. (Kf for water = 1.86 K kg mol–1)
Define the following terms:
(i) Primitive unit cells
(ii) Schottky defect
(iii) Ferromagnetism
The rate constant of a first order reaction increases from 2 — 10-2 to 4 — 10-2when the temperature changes from 300 K to 310 K. Calculate the energy of activation (Ea).
(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
Define the following terms:
(i) Brownian movement
(ii) Peptization
(iii) Multimolecular colloids
The conductivity of 0.20 mol L-1 solution of KCl is 2.48 x 10-2 S cm-1. Calculate its molar conductivity and degree of dissociation (K+) = 73.56 S cm2 mol-1 and (Cl-)= 76.5 S
(b) What type of battery is mercury cell? Why is it more advantageous than dry cell?
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