Chemistry Test 256

Result

Chemistry Test 256

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

The most suitable reagent for the conversion of R - CH₂ - OH → R - CHO is

A
CrO₃

B
PCC (Pyridinium Chlorochromate)

C
KMnO₄

D
K₂Cr₂O₇

Solution

Pyridinium chlorochromate (PCC) is a mild oxidising agent. It can easily convert primary alcohols into aldehydes.

While others are strong oxidising agents that convert alcohols into carboxylic acid.
Question 2
4 / -1

At 300 K and 1 atm, 15 mL of a gaseous hydrocarbon requires 375 mL of air containing 20% O₂ by volume for complete combustion. After combustion, the gases occupy 345 mL. 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
C₃H₆

B
C₃H₈

C
C₄H₈

D
C₄H₁₀

Solution

CₓHᵧ + (x + y / 4)O₂ → xCO₂ + y / 2 H₂O

Volume of CₓHᵧ = 15 mL

Volume of O₂ = (20 / 100) × 375 = 75 mL

Final volume = Volume of unreacted air + volume of carbon dioxide formed.

Therefore, volume of carbon dioxide formed = 345 - 300 = 45 mL.

According to Avogadro's law, volume ratio = molar ratio.

Hence, x = 3

number of moles of oxygen / number of moles of the hydrocarbon = 5 / 1

x + y / 4 = 5

3 + y / 4 = 5

y = 8

Hence the hydrocarbon is propane (C₃H₈).
Question 3
4 / -1

Which of the following compounds is not an antacid?

A
Aluminium hydroxide

B
Cimetidine

C
Phenelzine

D
Ranitidine

Solution

Phenelzine is not an antacid; it is an anti-depressant.
Question 4
4 / -1

A reaction of cobalt(III) chloride and ethylenediamine in a 1 : 2 mole ratio generates two isomeric products A (violet coloured) B (green coloured). A can show optical actively, B is optically inactive. What type of isomers does A and B represent?

A
Geometrical isomers

B
Ionisation isomers

C
Coordination isomers

D
Linkage isomers

Solution

According to the situation given in question, reactions are as follows:
Question 5
4 / -1

Among the following, the strongest reducing agent is

A
Cr³⁺

B
Mn²⁺

C
Cr

D
CI^–

Solution

For Cr³⁺, E° (Cr³⁺/Cr₂O₇²⁻) = -1.33 V

For Cl⁻, E° (Cl⁻/Cl₂) = -1.36 V

For Cr, E° (Cr/Cr³⁺) = 0.74 V

For Mn²⁺, E° (Mn²⁺/MnO₄⁻) = -1.51 V

Positive E° is for Cr, hence it is the strongest reducing agent.
Question 6
4 / -1

The polymer used for making contact lenses for eyes is:

A
Polymethylmethacrylate

B
Polyethylene

C
Polyethylacrylate

D
Nylon-6

Solution

Contact lenses are made using the polymer Polymethyl Methacrylate which is generally known as PMMA. The lenses made using PMMA are known as hard lenses and were used commonly when first made. Now soft lenses made of polyacrylamide polymer are preferred more than hard lenses.
Question 7
4 / -1

From amongst the following alcohols the one that would react fastest with conc. HCl and anhydrous ZnCI₂, is:

A
2 -Butanol

B
2 -Methylpropan-2-ol

C
2 -Methylpropanol

D
1 -Butanol

Solution

The alcohol that would react fastest with conc. HCl and anhydrous ZnCI₂ is 2- methylpropan - 2- ol. It is a tertiary alcohol. A mixture of conc. HCl and anhydrous ZnCI₂is called Lucas reagent.

Primary alcohols react with Lucas reagent very slowly on heating to give alkyl chlorides. Secondary alcohols react with Lucas reagent much faster. Tertiary alcohols instantaneously react with HCl at room temperature.

Note: Lucas reagent is required for primary and secondary alcohol only.
Question 8
4 / -1

The two form of D-glucopyranose obtained from the solution of D-glucose are called:

A
Isomer

B
Anomer

C
Epimer

D
Enantiomer

Solution

α−D(+)-glucopyranose and β−D(+) -glucopyranose are anomers (a pair of stereoisomers that differ in a configuration only around the first carbon atom i.e. anomeric carbon).
Question 9
4 / -1

Which of the following compounds will be suitable for Kjeldahl's method for nitrogen estimation?

A

B

C

D

Solution

The Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in rings (e.g. pyridine, quinoline, isoquinoline) as nitrogen of these compounds does not convert to ammonium sulphate under the conditions of this method.
Question 10
4 / -1

For a reaction A + B ⇌ 2C + D, if the activation energy of the forward and backward reactions are 25 kJ mol⁻¹ and 35 kJ mol⁻¹ respectively. The enthalpy change of the reaction is

A
10 kJ mol⁻¹

B
−10 kJ mol⁻¹

C
60 kJ mol⁻¹

D
-60 kJ mol⁻¹

Solution

ΔH = E_a(f) − E_a(b)

= (25 − 35)kJ mol⁻¹

= −10 kJ mol⁻¹