1. The general formula for cycloalkane is:
a
CₙH₂ₙ₊₂
Wrong
b
CₙH₂ₙ₋₂
Wrong
c
CₙH₂ₙ
Right
d
CₙH₄ₙ
Wrong
✅ Correct Answer: (c) Cycloalkanes follow CₙH₂ₙ. Closing a ring removes two hydrogens compared to alkanes (CₙH₂ₙ₊₂).
2. NMR spectroscopy is concerned with the interaction of molecules with:
a
Infrared radiation
Wrong
b
Visible radiation
Wrong
c
Ultraviolet radiation
Wrong
d
Radio waves
Right
✅ Correct Answer: (d) Radio waves — NMR uses radio frequency in magnetic fields.
3. Oxidation state of manganese in KMnO₄ (potassium permanganate) is:
a
+7
Right
b
+4
Wrong
c
+5
Wrong
d
+2
Wrong
✅ Correct Answer: (a) +7 — Mn in KMnO₄ is in +7 oxidation state. In KMnO₄, K = +1 and each O = −2 (4 × −2 = −8).To balance the charges, Mn must be +7.
4. The greenhouse gas is:
a
O₂
Wrong
b
CO₂
Right
c
N₂
Wrong
d
Ar
Wrong
✅ Correct Answer: (b) CO₂— Major greenhouse gas trapping heat in Earth’s atmosphere.
5. Beryllium is diagonally related to this:
a
Li
Wrong
b
Si
Wrong
c
Mg
Wrong
d
Al
Right
✅ Correct Answer: (d) Radio waves — Aluminium (Al) — Beryllium shows a diagonal relationship with aluminium in the periodic table due to similar ionic size, charge density, and chemical properties.
6. The coordination number of cobalt in Na₄[Co(C₂O₄)₃] is:
a
3
Wrong
b
4
Wrong
c
6
Right
d
2
Wrong
✅ Correct Answer: (c) 6 — In Na₄[Co(C₂O₄)₃], each oxalate ion (C₂O₄²⁻) is bidentate (donates 2 pairs). With 3 oxalate ligands, the total coordination number is 3 × 2 = 6.
7. This element is not used in electroplating:
a
Sn
Wrong
b
Cr
Wrong
c
Zn
Wrong
d
Mn
Right
✅ Correct Answer: (d) Manganese (Mn) — Not commonly used for electroplating unlike Zn, Sn, Cr. Manganese (Mn), however, is not used in electroplating because it does not deposit smoothly or form protective, adherent coatings under normal electroplating conditions. Instead, manganese is more often used in steel alloys (to improve strength and hardness) rather than as an electroplating metal.Electroplating is commonly done with metals like Zn (zinc), Sn (tin), Cr (chromium), Ni (nickel), Ag (silver), and Au (gold) because they provide corrosion resistance, decorative finish, or hardness..
8. The extra glucose of bloodstream is converted into:
a
Fat
Wrong
b
Glycogen
Right
c
Gluconic acid
Wrong
d
Triglyceride
Wrong
✅ Correct Answer: (b) Glycogen — Extra glucose is stored in liver/muscles as glycogen.
9. On oxidation, a secondary alcohol gives:
a
Ether
Wrong
b
Aldehyde
Wrong
c
Ketone
Right
d
Amine
Wrong
✅ Correct Answer: (c) Ketone — A secondary alcohol on oxidation loses two hydrogen atoms—one from the hydroxyl group (–OH) and one from the carbon atom—and gets converted into a ketone. Secondary alcohols oxidize to ketones.
10. Ozone depletion in upper atmosphere is mainly caused by:
a
SO₂
Wrong
b
NO
Wrong
c
CO
Wrong
d
CFC
Right
✅ Correct Answer: (d) CFCs — Chlorofluorocarbons release chlorine radicals that destroy ozone.
11. The oxidation states of the elements of group VA:
a
+1 and +3
Wrong
b
-3 and -5
Wrong
c
-3, +3 and +5
Right
d
+1,-1 and +3
Wrong
✅ Correct Answer: (c) –3, +3, +5 — Group VA elements show these common oxidation states. Elements of Group VA (Group 15) have five valence electrons. They commonly show oxidation states −3 (by gaining three electrons) and +3, +5 (by losing three or five electrons), depending on the reacting species.
12. Which of the following s-block element forms superoxide when burned in air?
a
K
Right
b
Li
Wrong
c
Na
Wrong
d
Mg
Right
✅ Correct Answer: (a) K — Potassium forms KO₂ (superoxide). Among s-block elements, potassium reacts with oxygen in air to form a superoxide (KO₂) because its large K⁺ ion stabilizes O₂⁻ effectively. Lithium forms oxide (Li₂O), sodium mainly forms peroxide (Na₂O₂), while magnesium forms MgO.
13. In the equilibrium of dichromate–chromate ion the colour of CrO₄²⁻ is:
a
Green
Wrong
b
Yellow
Right
c
Orange
Wrong
d
Red
Wrong
✅ Correct Answer: (b) Yellow — Chromate ions (CrO₄²⁻) are yellow. In the dichromate–chromate equilibrium, the chromate ion (CrO₄²⁻) has a yellow colour, while the dichromate ion (Cr₂O₇²⁻) is orange. Equilibrium reaction:2 CrO₄²⁻ +2H⁺ ⇌ Cr₂O₇²⁻) + H₂O. Basic medium → chromate (yellow). Acidic medium → dichromate (orange).
14. How many optical isomers are possible for HOOC–CH(OH)–CH(Br)–COOH:
a
5
Wrong
b
2
Wrong
c
3
Wrong
d
4
Right
✅ Correct Answer: (d) 4 — Two chiral centers → 2² = 4 optical isomers. Chiral center is a carbon atom attached to four different groups.
C2: –COOH, –H, –OH, –CH(Br)–COOH → chiral.
C3: –H, –Br, –CH(OH)–COOH, –COOH → chiral.
So, there are 2 chiral centers.
Number of optical isomers = 2ⁿ (where n = number of chiral centers)2² = 4
15. Which of the following pairs of compounds represent functional group isomerism ?
a
1-butene and 2-butene
Wrong
b
Ethanol and dimethyl ether
Right
c
n-butane and iso-butane
Wrong
d
Diethyl ketone and methyl propyl ketone
Wrong
✅ Correct Answer: (b) Ethanol & dimethyl ether — Same formula, different functional groups.
16. Benzene burns with smoky flame because of its:
a
High resonance energy
Wrong
b
Inflammability
Wrong
c
Aromaticity
Wrong
d
High carbon %
Right
✅ Correct Answer: (d) High carbon % — Benzene’s high C:H ratio causes smoky flame.
17. The kinetics of elimination bimolecular reaction is:
a
Zero order
Wrong
b
First order
Wrong
c
Third order
Wrong
d
Second order
Right
✅ Correct Answer: (d) Second order — E₂ elimination follows bimolecular kinetics.
18. Clemmensen reduction is the conversion of aldehydes and ketones into:
a
Alkanes
Right
b
Alkenes
Wrong
c
Alkyl halides
Wrong
d
Alcohols
Wrong
✅ Correct Answer: (a) Alkanes — Clemmensen reduction converts carbonyls to alkanes.
19. Formic acid is naturally found in:
a
Bee’s sting
Right
b
Valerian root
Wrong
c
Vinegar
Wrong
d
Butter
Wrong
✅ Correct Answer: (a) Bee’s sting — Formic acid occurs naturally in ants/bees.
20. An example of quaternary structure of protein is:
a
Myoglobin
Wrong
b
Albumin
Wrong
c
Hemoglobin
Right
d
Globulin
Wrong
✅ Correct Answer: (c) Hemoglobin — Quaternary structure with multiple polypeptide chains.
21. An example of thermosetting plastic is:
a
Polyethene
Wrong
b
PVC
Wrong
c
Bakelite
Right
d
Nylon
Wrong
✅ Correct Answer: (c) Bakelite — Classic First Synthetic thermosetting plastic.
22. The region of sphere which extends from 11 km to 50 km from Earth is known as:
a
Troposphere
Wrong
b
Mesosphere
Wrong
c
Stratosphere
Right
d
Thermosphere
Wrong
✅ Correct Answer: (c) Stratosphere — Lies between 11–50 km altitude.
23. Infrared spectroscopy is a technique used to determine:
a
Double and triple bonds
Wrong
b
Mass-to-charge ratio
Wrong
c
Functional group
Right
d
Conjugated system
Wrong
✅ Correct Answer: (c) Functional groups — IR spectroscopy identifies functional groups by absorption bands.
24. Melting & boiling points of which group decrease regularly down the group?
a
Group VIIIA
Wrong
b
Group VIIA
Wrong
c
Group IIIA
Wrong
d
Group IA
Right
✅ Correct Answer: (d) Group IA → Alkali metals show decreasing melting & boiling points due to weaker metallic bonding.
25. Chemical used in fireworks?
a
Sodium bicarbonate
Wrong
b
Bleaching powder
Wrong
c
Potassium nitrate
Right
d
Potash alum
Wrong
✅ Correct Answer: (c) Potassium nitrate → Used in gunpowder & fireworks as oxidizer.
26. Flame colour of which alkali metal is yellow?
a
K
Wrong
b
Rb
Wrong
c
Cs
Wrong
d
Na
Right
✅ Correct Answer: (d) Na → Sodium imparts a bright yellow colour in flame test.
27. Oil of vitriol refers to:
a
Sulphuric Acid
Right
b
Borax
Wrong
c
Alum
Wrong
d
Caustic soda
Wrong
✅ Correct Answer: (a) Sulphuric Acid → Oil of vitriol is the old name for H₂SO₄.
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