NEET UG
- Match List - I with List - II.List - I (Drug class): (a) Antacids (b) Antihistamines (c) Analgesics (d) AntimicrobialsList - II (Drug molecule): (i) Salvarsan (ii) Morphine (iii) Cimetidine (iv) SeldaneChoose the correct answer from the options given… Answer: 3. (a) - (iii), (b) - (iv), (c) - (ii), (d) - (i) Key idea: match each drug class with a standard example. Antacids: cimetidine (iii... 1
- The given graph is a representation of kinetics of a reaction.[Graph: y versus x at constant temperature T]The y and x axes for zero and first order reactions, respectively are Answer: 4. zero order ( y = rate and x = concentration), first order ( y = t_(1/2) and x = concenration) Key idea: a horizontal line means y... 1
- Which of the following p-V curve represents maximum work done ? Answer: 3. [graph in figure] Key idea: work done by the gas equals the area under the p-V curve, so find the graph with the largest area. Gr... 1
- Identify the incorrect statement from the following Answer: 3. The oxidation number of K in KO₂ is +4 . Key idea: in superoxide KO₂ , oxygen is O₂^- , so K is +1. Alkali metals always show +1.... 1
- Match List - I with List - II.List - I: (a) Li (b) Na (c) KOH (d) CsList - II: (i) absorbent for carbon dioxide (ii) electrochemical cells (iii) coolant in fast breeder reactors (iv) photoelectric cellChoose the correct answer from the options given… Answer: 1. (a) - (ii), (b) - (iii), (c) - (i), (d) - (iv) Key idea: recall the uses of alkali metals and their compounds. Li: electrochemica... 1
- The IUPAC name of the complex -[Ag(H_2O)_2][Ag(CN)_2] is : Answer: 1. diaquasilver(I) dicyanidoargentate(I) Key idea: in a complex salt name the cation first and then the anion; in anionic complexes... 1
- The pH of the solution containing 50 mL each of 0.10 M sodium acetate and 0.01 M acetic acid is[Given pK_a of CH_3COOH = 4.57] Answer: 2. 5.57 Key idea: acetate/acetic acid is an acidic buffer; use the Henderson equation. pH=pK_a+log[salt]/[acid] Equal volumes are mi... 1
- Which compound amongst the following is not an aromatic compound ? Answer: 1. [structure in figure] Key idea: an aromatic compound is cyclic, planar, fully conjugated and has (4n+2) π electrons. (1) Cyclohep... 1
- Which of the following sequence of reactions is suitable to synthesize chlorobenzene ? Answer: 2. Benzene, Cl₂ , anhydrous FeCl₃ Key idea: chlorobenzene is made by electrophilic substitution of benzene with Cl₂ and a Lewis acid... 1
- Given below are two statements :Statement I :Primary aliphatic amines react with HNO_2 to give unstable diazonium salts.Statement II :Primary aromatic amines react with HNO_2 to form diazonium salts which are stable even above 300 K.In the light of t… Answer: 4. Statement I is correct but Statement II is incorrect. Key idea: diazonium salts of aliphatic amines are unstable; aromatic ones a... 1
- Match List - I with List - II.List - I (Products formed): (a) Cyanohydrin (b) Acetal (c) Schiff's base (d) OximeList - II (Reaction of carbonyl compound with): (i) NH_2OH (ii) RNH_2 (iii) alcohol (iv) HCNChoose the correct answer from the options giv… Answer: 1. (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i) Key idea: link each product to the reagent used with a carbonyl compound. Cyanohyd... 1
- Given below are two statements :Statement I :The boiling points of aldehydes and ketones are higher than hydrocarbons of comparable molecular masses because of weak molecular association in aldehydes and ketones due to dipole - dipole interactions.St… Answer: 2. Both Statement I and Statement II are correct. Key idea: polarity of C=O gives dipole-dipole attraction but no hydrogen bonding b... 1
- Given below are two statements :Statement I :The acidic strength of monosubstituted nitrophenol is higher than phenol because of electron withdrawing nitro group.Statement II :o-nitrophenol, m-nitrophenol and p-nitrophenol will have same acidic stren… Answer: 4. Statement I is correct but Statement II is incorrect. Key idea: the -NO₂ group is electron withdrawing and stabilises the phenoxi... 1
- Match List - I with List - II.List - I (Hydrides): (a) MgH_2 (b) GeH_4 (c) B_2H_6 (d) HFList - II (Nature): (i) Electron precise (ii) Electron deficient (iii) Electron rich (iv) IonicChoose the correct answer from the options given below : Answer: 2. (a) - (iv), (b) - (i), (c) - (ii), (d) - (iii) Key idea: classify hydrides by electron count. MgH₂ : metal hydride of s-block, io... 1
- Given below are two statements :Statement I :The boiling points of the following hydrides of group 16 elements increases in the order -H_2O < H_2S < H_2Se < H_2Te.Statement II :The boiling points of these hydrides increase with increase in molar mass… Answer: 3. Both Statement I and Statement II are incorrect. Key idea: water has an abnormally high boiling point because of hydrogen bonding... 1
- The Kjeldahl's method for the estimation of nitrogen can be used to estimate the amount of nitrogen in which one of the following compounds ? Answer: 4. [structure in figure] Key idea: Kjeldahl's method converts N to (NH₄)₂SO₄ on digestion; it fails for N in nitro, azo groups and i... 1
- Given below are half cell reactions :MnO_4^- + 8H^+ + 5e^- → Mn^2+ + 4H_2O,E^°_Mn^2+/MnO_4^- = -1.510 V1/2O_2 + 2H^+ + 2e^- → H_2O,E^°_O_2/H_2O = +1.223 VWill the permanganate ion, MnO_4^- liberate O_2 from water in the presence of an acid ? Answer: 2. Yes, because E^°_cell = +0.287 V Key idea: a reaction is spontaneous if E^°_cell>0 , using the reduction potentials of the two ha... 1
- Which one is not correct mathematical equation for Dalton's Law of partial pressure ? Here p = total pressure of gaseous mixture Answer: 1. p_i = chi_i p_i^° , where chi_i = mole fraction of i^th gas in gaseous mixture, p_i^° = pressure of i^th gas in pure state Key id... 1
- The incorrect statement regarding chirality is : Answer: 4. Enantiomers are superimposable mirror images on each other. Key idea: enantiomers are non-superimposable mirror images. Statement... 1
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) :In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from its unit cells.… Answer: 3. Both (A) and (R) are correct but (R) is not the correct explanation of (A) Key idea: missing cations with overall neutrality desc... 1
- Which amongst the following is incorrect statement ? Answer: 1. O₂^+ ion is diamagnetic. Key idea: write MO configurations and count unpaired electrons. O₂^+ has 15 electrons, with one electron... 1
- Amongst the following which one will have maximum 'lone pair - lone pair' electron repulsions ? Answer: 1. XeF₂ Key idea: compare the number of lone pairs on the central atom and their arrangement. XeF₂ : 3 lone pairs on Xe (trigonal bi... 1
- The IUPAC name of an element with atomic number 119 is Answer: 2. ununennium Key idea: IUPAC temporary names use numerical roots: 0 = nil, 1 = un, 9 = enn, ending in -ium. Z = 119 means digits 1,... 1
- RMgX + CO_2 dry ether Y H_3O^+ RCOOHWhat is Y in the above reaction ? Answer: 2. RCOO^(-M)g^+X Key idea: a Grignard reagent adds to CO₂ to give a magnesium carboxylate salt, which acid hydrolysis converts to th... 1