Chemistry Test 227

In CuCl₂, Cu²⁺ has d⁹ configuration, exhibit d − d transition and show colour. Similarly in VOCl₂, V⁴⁺ has d¹ configuration, can exhibit d − d transition and show colour.

MnCl₂ = Pink colour

Zn²⁺ ⇒ 3d¹⁰ (Colourless)

Hg²⁺ ⇒ 5d¹⁰(Colourless)

V = 4s²3d³

V⁴⁺ = 4s⁰3d¹ ((d − d transition)

Cu⁺² = d⁹ configuration = one unpaired e⁻.

Since, in both CuCl₂ and VOCl₂,Cu²⁺ and V⁴⁺ ion contain 1 unpaired electron each, so their colour may be same.

The hybridisation of the central atom can be decided based on the number of atomic orbitals used in the hybridisation. This can be found using the formula

Where,

H = Number of hybrid orbitals;

V.E.= Number of valence electrons on the central atom;

M = Number of monovalent atoms attached to the central atom;

C = Magnitude of charge if the given species is a cation;

A = Magnitude of charge if the given species is an anion.

Based on this, the hybridisation of NO₃⁻, NO₂⁺ and NH₄⁺ can be found out as:

sp³d² hybridised molecule have octahedral geometry(square bipyramidal)

IE of Mg>IE of Al

Mg: 1s², 2s²2p⁶, 3s²

Al: 1s², 2s2²p⁶, 3s²3p¹

The first electron remove from Mg is more difficult because it has fulfilled orbital configuration while Al has partial filled orbital configuration.

A graph plotted between log k versus 1/T for calculating activation energy is shown as

Comparing with the equation of straight line, y = mx + c, we get a straight line having positive intercept on y-axis and negative slope.

Toluene reacts with excess of Cl₂ in presence of sunlight, the last product of this reaction is benzotrichloride which on hydrolysis gives benzoic acid, and it gives sodium benzoate on reaction with NaOH.

Among the carbonyl compounds, the reactivity decreases with an increase in the number of alkyl groups and the size of the alkyl group because the positive charge on the carbon atom decreases due to +I effect of alkyl groups.

Thus, the correct order reactivity is HCHO > CH₃CHO > C₆H₅CHO.

Polyacrylonitrile (PAN), a synthetic resin prepared by the polymerization of acrylonitrile.

Polyacrylonitrile (PAN), also known as polyvinyl cyanide and Creslan 61, is a synthetic, semicrystalline organic polymer resin, with the linear formula (C₃H₃N)n.

Drinking water gets contaminated with lead when lead pipes are used for the transportation of water. The prescribed upper limit concentration of lead in drinking water is about 50 ppb. Lead can damage the kidney, liver, reproductive system, etc.