=> Ans: Oxygen cannot exhibit higher oxidation state due to absence of vacant d orbitals.
5➤ The number of lone pairs of electrons present in CIFs:
=> Ans: The number of lone pairs of electrons present on chlorine in CIF, is 1.
6➤ Write the order of ionic character of halides with monovalent metal
=> Ans: The ionic character of halides with monovalent metal (M) decreases in the order: MF> MCI > MBr> MI
7➤ What is the oxidation state of Te in Teo.?
=> Ans. The oxidation state of Te in TeO, is +4.
8➤ Explain the trend in electron gain enthalpy of group 17 elements.
=> Ans. Electron gain enthalpy (AegH): (i) The halogens have the highest negative values for electron gain enthalpy. (ii) Electron gain enthalpies of halogens are negative indicating release of energy. (iii) Since halogens have outer valence electronic configuration, ns² np³, they have strong tendency to accept an electron to complete an octet and acquire electronic configuration of the nearest inert elements. (iv) The variation in electron gain enthalpy is in the order of Cl> F > Br> L Q. 48. The pK, values of HCl is - 7.0 and that of HI is - 10.0..
9➤ Which is the stronger acid?
=> Ans. For HCl, pKa-7.0, hence its dissociation constant is, K₂=1 x 107. For HI, PK-10.0, hence its dissociation constant K 1x 10. Hence, HCl dissociates more than HI. Therefore, HCI is a stronger acid than HI.
10➤ The first member of the a group usually differs in properties from the rest of the members of the group. Why?
=> Ans. The first member of a group usually differs in properties from the rest of the members of the group for the following reasons: (1) Its small size (ii) High electronegativity (iii) Absence of vacant d-orbitals in its valence shell.
11➤ What is the action of bromine on magnesium metal?
=> Ans. Bromine reacts instantly with magnesium metal to give magnesium bromide. Mg+Br20 MgBr Magnesium bromide
12➤ Write the names of the allotropic forms of selenium.
=> Ans. Selenium has two allotropic forms as follows: (i) Red (non-metallic) form (ii) Grey (metallic) form.
13➤ What is the oxidation state of S in H,SO,?
=> Ans. The oxidation state of S in H₂SO, is +6. O⁴ (-8) H₂(+2) S(+6)
14➤ Explain laboratory preparation of ozone.
=> Ans. (1) When a slow dry stream of oxygen is passed through a silent electric discharge, oxygen is converted into ozone (about 10%). The mixture is called ozonised oxygen. 30, electric discharge 20₁ AH- + 142 kJ (ii) It is an endothermic reaction. (iii) Silent electric discharge prevents the decomposition of ozone.
15➤ What is the action of heat on KCIO,?
=> Ans. Potassium chlorate in the presence of manganese dioxide. on heating decomposes to form potassium chloride and oxygen. A 2KC10, 2KC1+300²
16➤ Give disproportionation reaction of BrF.
=> Ans. 5BrF2Br,+BrF,.
17➤ Q. 56. Explain ICI is more reactive than I..
=> Ans. (i) In interhalogen compound ICI and I, the atoms are bonded by covalent bonds. (ii) The covalent bond between dissimilar atoms, I and Cl atoms in ICI is weaker than between similar atoms in 1₂. (iii) Therefore, the bond dissociation enthalpy of ICI bond is less than that of I, bond.. Hence, ICI is more reactive than 1₂.
