NEET Important Chemistry
1. What is the shape of methane (CH₄)?
Answer: Tetrahedral
Explanation: Methane has sp³ hybridization, forming four equivalent sigma bonds arranged tetrahedrally around the carbon atom.
2. Which element has the highest electronegativity?
Answer: Fluorine
Explanation: Fluorine (F) has the highest electronegativity (3.98 on the Pauling scale) due to its small size and high nuclear charge.
3. What is the IUPAC name of CH₃–CH₂–OH?
Answer: Ethanol
Explanation: It's a two-carbon alcohol; "eth" for two carbons and "anol" for the –OH functional group.
4. Which bond is the strongest among sigma and pi bonds?
Answer: Sigma
Explanation: Sigma bonds involve head-on overlapping and are stronger than the lateral overlap of pi bonds.
5. What is the coordination number of Fe in [Fe(CN)₆]³⁻?
Answer: 6
Explanation: The metal ion Fe is bonded to six ligands (CN⁻), giving it a coordination number of 6.
6. What is the pH of a neutral solution at 25°C?
Answer: 7
Explanation: At 25°C, the concentrations of H⁺ and OH⁻ in pure water are equal (10⁻⁷ M), resulting in pH = 7.
7. Which gas is evolved when zinc reacts with dilute HCl?
Answer: Hydrogen
Explanation: Zn + 2HCl → ZnCl₂ + H₂↑ — hydrogen gas is released.
8. What is the hybridization of carbon in ethyne (C₂H₂)?
Answer: sp
Explanation: Each carbon in ethyne forms two sigma bonds and two pi bonds (one triple bond), indicating sp hybridization.
9. Which law states that equal volumes of gases contain equal number of molecules?
Answer: Avogadro's
Explanation: Avogadro's Law says that at the same temperature and pressure, equal volumes of all gases contain equal numbers of molecules.
10. What is the unit of rate constant in a first-order reaction?
Answer: s⁻¹
Explanation: For a first-order reaction, the rate constant k has units of time⁻¹.
11. What is the formula of bleaching powder?
Answer: Ca(OCl)Cl
Explanation: Bleaching powder is calcium oxychloride, used as a disinfectant and bleaching agent.
12. Which orbital is filled after 3p in the Aufbau principle?
Answer: 4s
Explanation: According to the Aufbau order (based on (n+l) rule), 4s fills before 3d.
13. Which acid is called King of Chemicals?
Answer: Sulfuric acid
Explanation: H₂SO₄ is widely used in industries and acts as a strong acid, dehydrating agent, and oxidizer.
14. Which catalyst is used in the Haber process?
Answer: Iron
Explanation: Finely divided iron acts as a catalyst for the synthesis of ammonia from nitrogen and hydrogen.
15. What is the oxidation state of Mn in KMnO₄?
Answer: +7
Explanation: In KMnO₄, K = +1, O = –2. To balance: +1 + x + 4(–2) = 0 ⇒ x = +7.
16. Which orbital has the highest energy in ground-state oxygen?
Answer: 2p
Explanation: For oxygen (1s² 2s² 2p⁴), the 2p orbital has the highest energy among occupied orbitals.
17. What is the name of the salt formed by HCl and NaOH?
Answer: NaCl
Explanation: Neutralization reaction: HCl + NaOH → NaCl + H₂O.
18. What type of isomerism is shown by CH₃CH(OH)CH₃ and CH₃COCH₃?
Answer: Functional
Explanation: One is an alcohol (isopropyl alcohol) and the other is a ketone (acetone) — same molecular formula, different functional groups.
19. What is the charge on sulfate ion?
Answer: -2
Explanation: SO₄²⁻ carries a -2 charge due to two extra electrons.
20. What is the common name of trichloromethane?
Answer: Chloroform
Explanation: CHCl₃ is commonly known as chloroform, used as a solvent and formerly as an anesthetic.
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