Chemistry Test - 14

Oxidation at anode is represented by the half cell reaction:

\(\mathrm{Pb}(s)+\mathrm{SO}_{4}^{2-}(a q) \rightarrow \mathrm{PbSO}_{4}(s)+2 e^{-}\)

Reduction at cathode is represented by the half cell reaction:

\(\mathrm{PbO}_{2}(s)+4 H^{+}(a q)+S O_{4}^{2-}(a q)+2 e^{-} \rightarrow P b S O_{4}(s)+2 H_{2} O(l)\)

The overall cell reaction is:

\(\mathrm{Pb}(s)+\mathrm{PbO}_{2}(s)+2 \mathrm{H}_{2} \mathrm{SO}_{4}(a q) \rightarrow 2 \mathrm{PbSO}_{4}(s)+2 \mathrm{H}_{2} \mathrm{O}(l)\)

During discharging of a lead storage battery, sulfuric acid is consumed and water is produced.

Lead sulphate is formed at both electrodes.

Since sulfuric acid is consumed, the density of the electrolytic solution decreases.

Chain silicates are formed by sharing two oxygen atoms by each tetrahedron.

Anions of chain silicate have two general formula:

(i) \(\left(\mathrm{SiO}_{3}{ }^{2-}\right)_{n}\)

(ii) \(\left(\mathrm{Si}_{14} \mathrm{O}_{11}^{6-}\right)_{n}\)

For example, spodumene \(\mathrm{LiAl}\left(\mathrm{SiO}_{3}\right)_{2}\); enstatite \(\mathrm{MgSiO}_{3}\) are pyroxene type chain silicates.

When primary amine reacts with chloroform in ethanoic KOH, it follows carbylamine reaction and the product formed is an isocyanide. Isocyanide is also known as carbylamine. Isocyanide gives off a very offensive odor, so this reaction is also used as a test for primary amines.

\(\mathrm{R}-\mathrm{NH}_2+\mathrm{CHCl}_3+3 \mathrm{KOH} \xrightarrow{\Delta} \mathrm{R}-\mathrm{NC}+3 \mathrm{KCl}+3 \mathrm{H}_2 \mathrm{O}\)

In oxidation, an element looses its electrons.

There is \(+3\) oxidation state means no. of loss of electrons is 3, and that 2 electrons are released from \(4\mathrm{s}^2\) orbital and 1 electron from \(3 \mathrm{d}\) orbital to attain half filled stability.

Therefore, \(\left[\mathrm{Ar}\right]\) has 18 electrons and 5 electrons in \(3 \mathrm{d}\) orbital as per given.

Therefore, actual configuration will be \([A r]^{18} 3 d^{6} 4 s^{2}\). Therefore, atomic number will be \(18+6+2=26\).

This is Fe having atomic number 26.

Zirconium belongs to 4d transition series and Hafnium belongs to 5d transition series but they show similarity in physical and chemical properties because of similar atomic radius arising because of lanthanoid contraction.

Given:\(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COCl}\)

Numbering the carbon atoms as:

\(\mathrm{\stackrel{3}{C}H_{3}\stackrel{2}{C}H_{2}\stackrel{1}{C}OCl}\)

• This is an acid chloride.
• It consists of three carbon atoms in the parent chain and chloroformyl group \(\mathrm{(-COCl)}\).
• In the IUPAC name, the suffix "oyl chloride" is added.Therefore, the IUPAC name will be propanoyl chloride.

Nucleophiles are the species which have an excess of electrons.

Among the given species, the lone pair of nitrogen of pyrrole (B) is involved in the delocalization of the ring, thus, they are not available for donation. 

In aniline (D), the lone pair is involved in conjugation with the π electrons of the ring while in pyridine, these are relatively free for donation. Thus, the nitrogen of pyridine (A) is the most nucleophilic.

Phenyl and −COCH₃ ​both are electron-withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Given that,

Bond length, \(\mathrm{d=2.00}\) Å \(\mathrm{=2 \times 10^{-10}~m}\)

Theoretical Dipole Moment, \(\mathrm{ =5.12 \times10^{-30}~Cm}\)

We know that,

Charge, \(\mathrm{Q=1.6 \times10^{-19}}\)

Therefore, from:

Dipole moment \(=\) Charge \(\times\) Bond Length

\(=1.6 \times10^{-19} \times 2 \times 10^{-10}~m\)

\(=32 \times 10^{-30}\mathrm{~Cm}\)

We also know that:

\(\%\)Ionic Character \(=\frac{\text{Observed Dipole Moment}}{\text{Theoritical Dipole Moment}}\times100\)

\(=\frac{5.12 \times10^{-30}}{32 \times 10^{-30}}\times 100\)

\(=0.16 \times 100\)

\(=16\%\)

Different complex ions have the same molecular formula. Ligands are interchanged between the complex cation and complex anion. These types of complexes are called coordination isomers.

In \(\left[ Pt \left( NH _{3}\right)_{4}\right]\left[ CuCl _{4}\right]\), ammonia ligands are attached to \(Pt\) metal and chloride ligands are attached to \(Cu\) metal.

In \(\left[ Cu \left( NH _{3}\right)_{4}\right]\left[ P tCl _{4}\right]\), ammonia ligands are attached to \(Cu\) metal and chloride ligands are attached to \(Pt\) metal.

In the decomposition of hydrogen peroxide, two successive reactions of H₂O₂, with bromide and then with bromine, take place. Because these two reactions together serve as a catalytic pathway for hydrogen peroxide decomposition, both of them must have significantly lower activation energies than the uncatalyzed decomposition, as shown schematically in Figure.

Bromine acts as negative catalyst in the reaction. Bromine forms an intermediate (Br−) on reacting with H₂O₂ following reduction of bromine and then to show oxidation of Br− to Br₂ by H₂O₂.