Chemistry Test - 16

Acidic character \(\propto \frac{1}{\mathbf{p K}_{\mathrm{a}}}\)

\(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}\) will have highest value of \(\mathrm{pKa} \).

Others have electronegative halogen atom on alpha or beta carbon atom which increases the acidity and decreases the pKa value.

Electricity is conducted through an electrolytic solution due to the movement of ions called electrolytic conduction.

Electrical conductance depends upon-

• Nature of electrolyte: The conductance of an electrolyte depends upon the number of ions present in the solution. Therefore, the greater the number of ions in the solution, the greater is the conductance.
• Concentration of the solution: The molar conductance of electrolytic solution varies with the concentration of the electrolyte. In general, the molar conductance of an electrolyte increases with decrease in concentration or increase in dilution.
• Temperature: The conductivity of an electrolyte depends upon the temperature. With increase in temperature, the conductivity of an electrolyte increases.
• Valence electrons per atom present in metals describes the electric conductance of it.
• Nature and structure is also a significant factors which influences electrical conductance.

Ionic Bond, also called the electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. 

Covalent Bond: In these types of bonding sharing of electrons between two atoms of the same or different elements. This type of bonding may be single, double or triple depending upon the number of sharing pairs of electrons.

Co-ordinate Bond: In this type one side sharing of one pair of electrons between two atoms happens. Here one atom which provides electron is known as a donor and another one is known which receive electron is known as acceptor.

The structure of Sodium Cyanide (NaCN) is given below:

NaCN contains ionic, covalent and coordinate bonds.

The atomic number is 56.It is mostly used in drilling fluids for oil and gas wells and also used in paints and glassmaking.

• It is found in combination with other elements.
• Barite is one of the major ores of Barium.
• Atomic number 56, Barium belongs to s - block elements.
• Modern Periodic Table is classified into the following elements - p-block, s-block, d-block, and f-block.
• s-block elements include alkali metals and alkaline earth metals.

The option (A) gives nylon-6 which is a condensation polymer. It is obtained by the condensation polymerisation of caprolactum. Nylon-6 is a general purpose grade which is widely used for mechanical construction and maintenance.

 Option (B) gives polystyrene and Option (C) gives polythene. Both of them are addition polymers.

The prosthetic group of haemoglobin isheme.

The Heme group in hemoglobin is a prosthetic group located in the porphyrin, which is a tetramer of cyclic carbon groups. It contains an organic component called a protoporphyrin made up of four pyrrole rings and an iron atom in the ferrous state \(\left(\mathrm{Fe}^{2+}\right)\).

Let the oxidation number of the central atom be \(x\).

Oxidation state of side atoms be:

\(H=+1, C l=I=-1\) and of \(O=-2\).

Then,

\(P C l_{5}: x+5 \times(-1)=0\)

\(x=+5\)

\(H I O_{4}: 1+x+4 \times(-2)=0\)

\(x=+7\)

\(C l_{2} O_{7}^{-2}: 2 x+7 \times(-2)=-2\)

\(x=+6\)

\(C l_{2} O: 2 x+(-2)=0\)

\(x=+1\)

\(C r_{-2} O_{7}^{2}=2 x+7 \times(-2)=-2\)

\(x=+6\)

Thus, the decreasing order of the oxidation state of central atom is as:

\(\mathrm{HIO}_{4}>\mathrm{Cr}_{2} \mathrm{O}_{7}^{-2}=\mathrm{Cl}_{2} \mathrm{O}_{7}^{-2}>\mathrm{PCl}_{5}>\mathrm{Cl}_{2} \mathrm{O}\)

The given reaction is known as the Kolbe reaction. The sodium salt of phenol is heated with carbon dioxide gas at 120° to 140°C under pressure (4-7 atmospheres), a carboxyl group is introduced mainly in the ortho position with respect to the phenolic group to form salicylic acid (ortho hydroxybenzoic acid).

\(\mathrm{Zn}^{2+}+2 \mathrm{NaOH} \rightarrow{\underset{\text{white ppt}} {\mathrm{Zn(OH})_{2}}} \stackrel{2 \mathrm{NaOH}}{\longrightarrow}{\underset{\text{anionic part}}{\mathrm{Na}_{2}{\mathrm{ZnO}_{2}}}}+2 \mathrm{H}_{2} \mathrm{O}\)

Thus,In the solution, zinc exists in theanionic part.

Buna-N and Nylon-6,6 are co-polymers.

When two or more different monomers combine, they form co-polymer.

Neoprene is an addition homo-polymer of chloroprene.

Buna-N is formed by co-polymerization of 1,3-Butadiene and Acrylonitrile.

Nylon-6,6 is formed by co-polymerization of adipic acid and hexamethylene diamine by elimination of water.