Short Answer TypeAccount for the following:
(i) Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
(ii) The enthalpy of atomization is lowest for Zn in 3d series of the transition elements.
(iii) Actinoid elements show a wide range of oxidation states.
(i) Name the elements of 3d transition series that show a maximum number of oxidation states. Why does this happen?
(ii) Which transition metal of 3d series has positive E0 (M2+/M) value and why?
(iii) Out of Cr3+ and Mn3+, which is a stronger oxidising agent and why?
(iv) Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.
(v) Complete the following equation: MnO4- + 8H+ + 5e- -->
Arrange the following in increasing order of their basic strength in aqueous solution:
CH3NH2, (CH3)3N, (CH3)2NH
What happens when
(i) PCl5 is heated?
(ii) H3PO3 is heated?
Write the reactions involved ?
Give reasons for the following:
(i) Bond enthalpy of F2 is lower than that of Cl2.
(ii) PH3 has lower boiling point than NH3Account for the following:
(i) Helium is used in diving apparatus.
(ii) Fluorine does not exhibit positive oxidation state.
(iii) Oxygen shows catenation behaviour less than sulphur
(i) Helium mixed with oxygen under pressure is given to sea-divers for respiration. However, pure oxygen can be toxic at great concentrations at the depth. Therefore oxygen can be mixed with helium to reduce oxygen concentration while eliminating nitrogen. During controlled decompression, the helium would also diffuse out of tissue and the lungs are more easily than nitrogen avoiding the bends .Use of helium for relatively shallow scuba diving would likely permit longer driving times with less threat of the bends.
(ii) Fluorine being the most electronegative atom does not exhibit positive oxidation state because the electrons in fluorine are strongly attracted by the nuclear charge because of the small size of a fluorine atom and therefore, removal of an electron is not possible.
(iii) Sulphur shows catenation behaviour more than that of oxygen because the oxygen atom is smaller in size as compared to sulphur, the O-O bonds in oxygen experiences repulsions due to the lone pairs present on oxygen atom and therefore, are weaker as compared to the S-S bonds.
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