Question on Inorganic Chemistry

Write down equations for the following reactions;
1. Oxidation of chromium(III) chloride with bromine in alkaline solution (KOH).
2. Oxidation of potassium nitrite with potassium permanganate in acid solution (\(H_2SO_4\)).
3. Action of chlorine on lime water (\(Ca(OH)_2\)) in a cold reaction mixture.

Question on Thermodynamics

A sample of 2.00 mol of \(CH_3OH_{(g)}\) is condensed isothermally and reversibly to liquid at \(64^{\circ}C\). The standard enthalpy of vaporization of methanol at \(64^{\circ}C\) is 35.3kJ/mol. Find q and \(\Delta H\) for this process.

Question on Radioactivity

How many radioactive disintegrations occur per minute in a 0.0010g sample of \(Po^{209}\) that has been freshly separated from its decay products if the half-life of \(Po^{209}\) is 103 years?

Question on Hydrocarbons

Volume Strength of Hydrogen Peroxide

Percentage Strength of Oleum

Oleum also known as fuming sulphuric acid has the molecular formula (\(H_2S_2O_7\)). It can be considered as a mixture od \(SO_3\) and \(H_2SO_4\). Addition of water to Oleum converts the free \(SO_3\) into \(H_2SO_4\) and the resulting solution will contain only \(H_2SO_4\).

\[SO_3 + H_2O \rightarrow H_2SO_4\]

To know how much water to add to a known amount of oleum, the concentration of oleum is expressed in terms of a percentage. The percentage will look like (100 + x)% and will always be more than 100. The value of “x“ is the amount of \(H_2O\) required by 100g of oleum to convert all the free \(SO_3\) present in it into \(H_2SO_4\).

For example, if a sample of oleum is labelled 109%, it means that to 100g of it 9g of water should be added to convert all the free \(SO_3\) present in it into \(H_2SO_4\).

\[SO_3 + H_2O \rightarrow H_2SO_4\]

According to the above reaction, 18g of \(H_2O\) is needed to convert 80g \(SO_3\) into \(H_2SO_4\). So, 9g of \(H_2O\) is needed to convert 40g \(SO_3\) into \(H_2SO_4\). This means that in 100g of the sample of oleum, 40g is \(SO_3\) and the rest 60g is \(H_2SO_4\).

Question on Nucleophilic Substitution

Nucleophilic Substitution - SN1

Question on Alkenes

The reaction of propene with HOCl (\(Cl_2 + H_2O\)) proceeds through the intermediate

A) \(CH_3-CH^+-CH_2-Cl\)

B) \(CH_3-CH(OH)-CH_2^+\)

C) \(CH_3-CHCl-CH_2^+\)

D) \(CH_3-CH^+-CH_2-OH\)

Question on Gaseous State

Question on Amines

In the Hofmann bromamide degradation reaction, the number of moles of NaOH and \(Br_2\) used per mole of amine produced are

A) Four moles of NaOH and two moles of \(Br_2\)

B) Two moles of NaOH and two moles of \(Br_2\)

C) Four moles of NaOH and one mole of \(Br_2\)

D) One mole of NaOH and one mole of \(Br_2\)

Question on Periodic Properties

Which of the following atoms has the highest first ionization energy?

A) Na

B) K

C) Sc

D) Rb

Question on Electrochemistry

Galvanization is applying a coating of

A) Cr

B) Cu

C) Zn

D) Pb

Question on Bio Organic Chemistry

Thiol Group is present in

A) Cystine

B) Cysteine

C) Methionine

D) Cytosine

Question on Alkali Metals

The main oxides formed on combustion of Li, Na and K in excess of air are, respectively

A) \(LiO_2, Na_2O_2, K_2O\)

B) \(Li_2O_2, Na_2O_2, KO_2\) 

A) \(Li_2O, Na_2O_2, KO_2\) 

A) \(Li_2O, Na_2O, KO_2\)

Question on Environment Chemistry

The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to high concentration of

A) Lead

B) Nitrate

C) Iron

D) Fluoride

Question about properties of Water

Which one of the following statements about water is FALSE?

A) Water can act both as an acid and as a base.

B) There is extensive intramolecular hydrogen bonding in the condensed phase.

C) Ice formed by heavy water sinks in normal water

D) Water is oxidized to oxygen during photosynthesis

Question on Nitrogen Chemistry

The reaction on zinc with dilute and concentrated nitric acid, respectively, preoduces

A) \(NO_2 \ and \ NO\)

B) \(NO \ and \ N_2O\)

A) \(NO_2 \ and \ N_2O\) 

A) \(N_2O \ and \ NO_2\)

Question on Isomerism

Which of the following complexes shows optical isomerism?

A) \(cis[Co(en)_2Cl_2]Cl\)

B) \(trans[Co(en)_2Cl_2]Cl\)

C) \([Co(NH_3)_4Cl_2]Cl\)

D) \([Co(NH_3)_3Cl_3]\)

Question on Oxidation States

The pair in which phosphorous atoms have a formal oxidation state of +3 is

A) Pyrophosphorous and hypophosphoric acids

B) Orthophosphorus and hypophosphoric acids

C) Pyrophosphorous and pyrophosphoric acids

D) Orthophosphorous and pyrophosphorous acids

Question on Eudiometry

At 300 K and 1 atm, 15mL of a gaseous hydrocarbon requires 375mL air containing 20% \(O_2\) by volume for complete combustion. After combustion the gases occupy 330mL. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is

A) \(C_3H_8\)

B) \(C_4H_8\) 

C) \(C_4H_{10}\) 

D) \(C_3H_6\)

Question on Metallurgy

Which one of the following ores is best concentrated by froth floatation method?

A) Siderite

B) Galena

C) Malachite

D) Magnetite

Question on Equilibrium Constant

The equilibrium constant at 298 K for a reaction \(A + B \leftrightharpoons C + D\) is 100. If the initial concentration of all the four species were 1M each, then equilibrium concentration of D (in \(mol L^{–1})\) will be:

A) 0.818

B) 1.818

C) 1.182

D) 0.182

Question on Absolute Configuration

Question on Magnetic Moment

The pair having the same magnetic moment is:

[Atomic Numbers: Cr = 24, Mn = 25, Fe = 26, Co = 27]

A) \([Cr(H_2O)_6)]^{2+} \ and \ [Fe(H_2O)_6]^{2+}\)

B) \([Mn(H_2O)_6)]^{2+} \ and \ [Cr(H_2O)_6]^{2+}\)

C) \([CoCl_4)]^{2-} \ and \ [Fe(H_2O)_6]^{2+}\)

A) \([Cr(H_2O)_6)]^{2+} \ and \ [CoCl_4]^{2-}\)

Question on Chemical Kinetics

Decomposition of \(H_2O_2\) follows a first order reaction. In fifty minutes the concentration of \(H_2O_2\) decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of \(H_2O_2\_ reaches 0.05 M, the rate of formation of \(O_2\) will be 

A) \(6.93 \times 10^{-4} \ mol min^{-1}\)

B) \(2.66\ L \ min^{-1} \ at \ STP\)

C) \(1.34 \times 10^{-2} \ mol min^{-1}\)

D) \(6.93 \times 10^{-2} \ mol min^{-1}\)

Question on Hybridization

The species in which the N atom is in a state of sp hybridization is

A) \(NO_2^-\)

B) \(NO_3^-\)

C) \(NO_2\)

D) \(NO_2^+\)

Question on Soap Preparation

The distillation technique most suited for separating glycerol from spent-lye in the soap industry is

A) Fractional Distillation

B) Steam Distillation 

C) Distillation under reduced pressure

D) Simple Distillation

Question on Vapour Pressure

18 g glucose \((C_6H_{12}O_6)\) is added to 178.2 g water. The vapour pressure of water (in torr) for this aqueous solution is 

A) 76.0

B) 752.4 

C) 759.0

D) 7.6

Question on Detergents

Which of the following is an anionic detergent? 

A) Sodium lauryl sulphate

B) Cetyl trimethyl ammonium bromide 

C) Glyceryl oleate

D) Sodium stearate

Question on Analytical Chemistry

Question on Thermochemistry

The heats of combustion of carbon and carbon monoxide are \(–393.5 kJ mol^{-1}\) and \(–283.5 kJ mol^{–1}\), respectively. The heat of formation (in kJ) of carbon monoxide per mole is 

A) 676.0

B) –676.0 

C) –110.0

D) 110.0

Question on Adsorption

For a linear plot of \(log \frac{x}{m}\) versus \(log p\) in a Freundlich adsorption isotherm, which of the following statements is correct? (k and n are constants) 

A) \(\frac{1}{n}\) appears as the intercept

B) Only \(\frac{1}{n}\) appears as the slope 

C) \(log \frac{1}{n}\) appears as the intercept

D) Both k and \(\frac{1}{n}\) appear in the slope term.

Question on Polymers

Which of the following statements about low density polythene is FALSE? 

A) It is a poor conductor of electricity 

B) It’s synthesis requires dioxygen or a peroxide initiator as a catalyst 

C) It is used in the manufacture of buckets, dust-bins etc. 

D) It’s synthesis requires high pressure

Question on Magnetism

Which of the following compounds is metallic and ferromagnetic? 

A) \(CrO_2\)

B) \( \(CrO_2\) O_2\)  

C) \(MnO_2\)

D) \(TiO_2\)

Question on Alkyl Halides

Question on Atomic Structure

A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of \(\frac{h}{l}\) (where \(l\) is wavelength associated with electron wave) is given by

A) \(2meV\)

B) \(\sqrt{meV}\)

C) \(\sqrt{2meV}\)

D) \(meV\)