NEET UG
- Oxidative phosphorylation is Answer: 3. formation of ATP by energy released from electrons removed during substrate oxidation Oxidative phosphorylation is the formation... 1
- Which of the following pairs of d-orbitals will have electron density along the axes? Answer: 2. d_z², d_(x²-y²) Key idea: d_z² and d_(x²-y²) have lobes along the axes; d_xy, d_yz, d_xz have lobes between the axes. So the pair... 1
- The hybridizations of atomic orbitals of nitrogen in NO_2^+, NO_3^- and NH_4^+ respectively are Answer: 2. sp , sp² and sp³ Key idea: hybridisation = (bond pairs + lone pairs) on N. NO₂^+ : O=N=O, 2 bond pairs, no lone pair, so sp . NO₃... 1
- Among the following, which one is a wrong statement? Answer: 2. SeF₄ and CH₄ have same shape. Key idea: compare VSEPR shapes. SO₂ has pπ - dπ bonding: correct. SeF₄ is see-saw (4 bond pairs + 1... 1
- Which of the following pairs of ions is isoelectronic and isostructural? Answer: Dropped in the official answer key: full marks to every candidate Key idea: compare total electrons and shape. CO₃²⁻ and NO₃^- : 32... 1
- The correct geometry and hybridization for XeF_4 are Answer: 3. square planar, sp³d² Key idea: Xe in XeF₄ has 4 bond pairs and 2 lone pairs. Steric number 6 gives sp³d² hybridisation and an oct... 1
- The suspension of slaked lime in water is known as Answer: 2. milk of lime Key idea: Ca(OH)₂ is only sparingly soluble in water. A suspension of slaked lime in water looks milky, so it is cal... 1
- The solubility of AgCl (s) with solubility product 1.6×10^-10 in 0.1 M NaCl solution would be Answer: 1. 1.6×10⁻⁹ M Key idea: the common ion Cl^- from NaCl suppresses the solubility of AgCl. Let solubility be s . [Ag^+]=s , [Cl^-]≈ 0.... 1
- Boric acid is an acid because its molecule Answer: 2. accepts OH^- from water releasing proton Key idea: boric acid is a Lewis acid, not a proton donor. Boron in B(OH)₃ has an empty p... 1
- AlF_3 is soluble in HF only in presence of KF. It is due to the formation of Answer: 1. K₃[AlF₆] Key idea: AlF₃ is covalent and insoluble; extra F^- from KF forms a soluble complex. AlF₃+3KF→ K₃[AlF₆] The stable hexaf... 1
- Which of the following fluoro-compounds is most likely to behave as a Lewis base? Answer: 1. PF₃ Key idea: a Lewis base needs a lone pair to donate. PF₃ : P has a lone pair, so it can act as a donor. CF₄ : no lone pair and... 1
- Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour? Answer: 3. CaF₂ + H₂SO₄ → CaSO₄ + 2HF Key idea: oxidising behaviour means H₂SO₄ is reduced (S goes from +6 to +4 as SO₂ ). Options 1, 2, 4:... 1
- In context with beryllium, which one of the following statements is incorrect? Answer: 2. Its salts rarely hydrolyze. Key idea: Be is small and highly polarising, so its salts hydrolyse readily. Be forms Be₂C (carbide):... 1
- The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is (charge on electron = 1.60×10^-19 C) Answer: 2. 3.75×10²⁰ Key idea: charge Q=It , and number of electrons =Q/e . Q=1×60=60\ C n=frac601.60×10⁻¹⁹=3.75×10²⁰ Option 4 ( 6×10²³ ) is... 1
- Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because Answer: 3. zinc has higher negative electrode potential than iron Key idea: a more electropositive metal can protect a less electropositive... 1
- Which one of the following is incorrect for ideal solution? Answer: 3. Δ G_mix=0 Key idea: an ideal solution has no net interaction change on mixing, and mixing is spontaneous. Δ H_mix=0 and Δ U_mix=0... 1
- Suppose the elements X and Y combine to form two compounds XY_2 and X_3Y_2. When 0.1 mole of XY_2 weighs 10 g and 0.05 mole of X_3Y_2 weighs 9 g, the atomic weights of X and Y are Answer: 4. 40, 30 Key idea: molar mass = mass / moles, then form two equations in the atomic masses X and Y. XY₂ : M=10/0.1=100⇒ X+2Y=100 X₃... 1
- Smooth muscles are Answer: 4. involuntary, fusiform, non-striated Smooth muscles are involuntary, spindle-shaped (fusiform), uninucleate and non-striated. They... 1
- Interspecific hybridization is the mating of Answer: 1. two different related species In interspecific hybridisation, male and female animals of two different related species are mated... 1
- Match Column—I with Column—II and select the correct option using the codes given below :Column—I: a. Citric acid; b. Cyclosporin A; c. Statins; d. Butyric acidColumn—II: (i) Trichoderma; (ii) Clostridium; (iii) Aspergillus; (iv) MonascusCodes :a b c… Answer: 1. (iii) (i) (iv) (ii) Citric acid: Aspergillus niger (iii). Cyclosporin A (immunosuppressant): Trichoderma polysporum (i). Statins... 1
- Study the four statements (A-D) given below and select the two correct ones out of them :A. Definition of biological species was given by Ernst Mayr.B. Photoperiod does not affect reproduction in plants.C. Binomial nomenclature system was given by R.… Answer: 2. A and D A: Ernst Mayr gave the biological species concept. True. B: Photoperiod affects flowering and reproduction in plants. Fal... 1
- Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from Answer: 2. petroleum industry BOD measures the oxygen needed by microbes to break down organic matter, so it is a good index for organic was... 1
- A lake which is rich in organic waste may result in Answer: 3. mortality of fish due to lack of oxygen A lake with a lot of organic waste has a high microbial decomposition. The microbes use u... 1
- Which of the following National Parks is home to the famous musk deer or hangul? Answer: 3. Dachigam National Park, Jammu & Kashmir The Kashmir stag, called hangul, lives in Dachigam National Park in Jammu and Kashmir. Ke... 1