Q31. Which of the following compounds of nitrogen is used in the manufacture of explosives?
A) Ammonium nitrate
B) Sodium nitrate
C) Nitrogen dioxide
D) Urea
Answer: A) Ammonium nitrate
Explanation: Ammonium nitrate is commonly used in explosives because of its ability to decompose rapidly, releasing a large amount of gas and energy.
Q32. Which of the following elements forms an acidic oxide?
A) Nitrogen
B) Phosphorus
C) Bismuth
D) Arsenic
Answer: A) Nitrogen
Explanation: Nitrogen forms acidic oxides such as NO₂ and N₂O₅, which dissolve in water to form acids. Phosphorus and arsenic also form acidic oxides, but nitrogen oxides are more acidic.
Q33. Which of the following is a property of white phosphorus?
A) It is soluble in water.
B) It glows in the dark (chemiluminescence).
C) It is a conductor of electricity.
D) It is non-reactive at room temperature.
Answer: B) It glows in the dark (chemiluminescence).
Explanation: White phosphorus exhibits chemiluminescence, glowing in the dark due to the slow oxidation of phosphorus in air, releasing light energy.
Q34. The bond angle in ammonia (NH₃) is approximately:
A) 120°
B) 109.5°
C) 107°
D) 104.5°
Answer: C) 107°
Explanation: The bond angle in ammonia is approximately 107° due to the lone pair of electrons on the nitrogen atom, which repels the bond pairs, reducing the ideal tetrahedral angle (109.5°).
Q35. Which of the following oxides of nitrogen is a neutral oxide?
A) NO
B) N₂O₃
C) NO₂
D) N₂O₅
Answer: A) NO
Explanation: Nitric oxide (NO) is a neutral oxide, meaning it does not show acidic or basic properties in water. Other nitrogen oxides like NO₂ and N₂O₅ are acidic.
Q36. The Haber process is used to synthesize:
A) Nitric acid
B) Ammonia
C) Urea
D) Nitrogen dioxide
Answer: B) Ammonia
Explanation: The Haber process is an industrial method for synthesizing ammonia (NH₃) by reacting nitrogen (N₂) and hydrogen (H₂) under high pressure and temperature in the presence of a catalyst.
Q37. Which of the following is the main constituent of the Earth’s atmosphere?
A) Oxygen
B) Nitrogen
C) Argon
D) Carbon dioxide
Answer: B) Nitrogen
Explanation: Nitrogen makes up about 78% of the Earth’s atmosphere, making it the most abundant gas, followed by oxygen at around 21%.
Q38. The oxidation state of nitrogen in nitric acid (HNO₃) is:
A) +3
B) +5
C) -3
D) 0
Answer: B) +5
Explanation: In nitric acid (HNO₃), nitrogen is in the +5 oxidation state, as the molecule consists of one nitrogen atom bonded to three oxygen atoms, with nitrogen losing five electrons in total.
Q39. Phosphorus forms halides in the oxidation states of:
A) +1 and +3
B) +2 and +4
C) +3 and +5
D) +4 and +6
Answer: C) +3 and +5
Explanation: Phosphorus typically forms halides in the +3 (e.g., PCl₃) and +5 (e.g., PCl₅) oxidation states, reflecting its ability to exhibit multiple oxidation states.
Q40. Which of the following compounds is used as a fertilizer?
A) Ammonium nitrate
B) Ammonium chloride
C) Sodium chloride
D) Urea
Answer: D) Urea
Explanation: Urea (NH₂CONH₂) is a widely used nitrogen fertilizer, as it provides a source of nitrogen to plants, which is essential for their growth.
Q41. Which of the following hydrides of nitrogen is the most basic?
A) NH₃
B) N₂H₄
C) NH₂OH
D) HNO₃
Answer: A) NH₃
Explanation: Ammonia (NH₃) is the most basic hydride of nitrogen due to the presence of a lone pair of electrons on nitrogen, which makes it a good proton acceptor.
Q42. The phosphorus allotrope that is used in the manufacture of safety matches is:
A) White phosphorus
B) Red phosphorus
C) Black phosphorus
D) Violet phosphorus
Answer: B) Red phosphorus
Explanation: Red phosphorus is used in safety matches due to its lower reactivity compared to white phosphorus, making it safer to handle.
Q43. The oxidation state of carbon in carbon dioxide (CO₂) is:
A) +2
B) +4
C) -4
D) 0
Answer: B) +4
Explanation: In CO₂, carbon is in the +4 oxidation state because each oxygen atom takes two electrons from the carbon, making carbon lose four electrons.
Q44. Silicon is widely used in the electronics industry because of its:
A) High electrical conductivity
B) Low reactivity
C) Semiconducting properties
D) Abundance
Answer: C) Semiconducting properties
Explanation: Silicon is used in the electronics industry due to its semiconducting properties, making it suitable for making transistors, diodes, and other electronic devices.
Q45. Which of the following elements of Group 14 forms the strongest covalent bonds?
A) Carbon
B) Silicon
C) Germanium
D) Tin
Answer: A) Carbon
Explanation: Carbon forms the strongest covalent bonds due to its small atomic size and ability to form stable bonds with itself and other elements.
Q46. Lead-acid batteries contain which of the following compounds of lead?
A) Lead oxide
B) Lead dioxide
C) Lead carbonate
D) Lead nitrate
Answer: B) Lead dioxide
Explanation: Lead-acid batteries contain lead dioxide (PbO₂) as the cathode material, which plays a crucial role in the electrochemical reactions of the battery.
Q47. The strongest allotrope of carbon is:
A) Graphite
B) Diamond
C) Fullerene
D) Graphene
Answer: B) Diamond
Explanation: Diamond is the hardest known natural material due to its three-dimensional covalent bond network, where each carbon atom is bonded to four others.
Q48. In which of the following compounds does carbon exhibit sp hybridization?
A) Ethyne
B) Ethene
C) Ethane
D) Carbon dioxide
Answer: A) Ethyne
Explanation: In ethyne (C₂H₂), carbon exhibits sp hybridization due to the triple bond between the carbon atoms, where one sigma bond and two pi bonds are formed.
Q49. The molecular geometry of methane (CH₄) is:
A) Trigonal planar
B) Linear
C) Tetrahedral
D) Square planar
Answer: C) Tetrahedral
Explanation: Methane (CH₄) has a tetrahedral geometry with bond angles of approximately 109.5°, as each hydrogen atom is bonded to carbon in a symmetrical arrangement.
Q50. Silicon dioxide (SiO₂) has a structure similar to:
A) Diamond
B) Graphite
C) Fullerene
D) Graphene
Answer: A) Diamond
Explanation: Silicon dioxide (SiO₂) has a network covalent structure similar to diamond, with each silicon atom bonded to four oxygen atoms in a tetrahedral arrangement.
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