INC CET / BSc Nursing Entrance Chemistry Flashcards

24 sample cards from the Chemistry deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. What is the order of a reaction, and write the rate law for a general reaction.

   Order is the sum of powers of concentration terms in the experimentally determined rate law. For aA + bB → products: rate = k[A]^x[B]^y, order = x + y.

2. Write the integrated rate equation and half-life for a first-order reaction.

   k = (2.303/t) log([A₀]/[A]); half-life t₁/₂ = 0.693/k (independent of initial concentration).

3. What is activation energy, and how does a catalyst affect it?

   Activation energy is the minimum energy reactants must possess to react. A catalyst lowers the activation energy by providing an alternative pathway, speeding the reaction without being consumed.

4. How do atomic radius and ionization energy vary across a period and down a group?

   Across a period: atomic radius decreases, ionization energy increases. Down a group: atomic radius increases, ionization energy decreases.

5. State the modern periodic law.

   The physical and chemical properties of elements are a periodic function of their atomic numbers.

6. How are the periodic table blocks (s, p, d, f) defined by the last-filled orbital?

   s-block: last electron in s orbital (groups 1–2); p-block: p orbital (groups 13–18); d-block: d orbital (transition metals); f-block: f orbital (lanthanides & actinides).

7. Why is hydrogen placed in group 1 yet shows similarities to group 17 elements?

   Like group 1 it has one valence electron and forms H⁺; like group 17 (halogens) it needs one electron to complete its shell and forms H⁻ (hydride), so its position is anomalous.

8. What are the three types of hydrides, with an example of each?

   Ionic/saline (e.g., NaH), covalent/molecular (e.g., CH₄, H₂O), and metallic/interstitial (e.g., d-block hydrides like PdH).

9. Why are alkali metals (group 1) stored under kerosene and highly reactive?

   They have one easily lost valence electron giving low ionization energy; they react vigorously with air and water, so they are stored under kerosene to prevent contact with moisture/oxygen.

10. What causes the temporary and permanent hardness of water, and how is each removed?

    Temporary hardness: bicarbonates of Ca/Mg, removed by boiling (Clark's method/lime). Permanent hardness: chlorides/sulphates of Ca/Mg, removed by washing soda or ion-exchange resins.

11. What are the diagonal-relationship pairs among period 2 and 3 s/p-block elements?

    Li–Mg, Be–Al, and B–Si show diagonal relationships due to similar charge/size ratio.

12. What are the allotropes of carbon and a key feature of each?

    Diamond (sp³, hardest, insulator), graphite (sp², soft, conducts electricity), and fullerene/C₆₀ (spherical cage molecule).

13. Why does nitrogen exist as a diatomic gas while phosphorus is a solid?

    Nitrogen forms a very stable N≡N triple bond (small atom, effective pπ–pπ overlap) giving a gas; phosphorus atoms are larger, cannot form stable pπ–pπ multiple bonds, so they form P₄ tetrahedral units (solid).

14. Name the noble gases and explain their chemical inertness.

    Helium, neon, argon, krypton, xenon, radon. They have completely filled outer electron shells (stable octet/duplet), giving very high ionization energy and low reactivity.

15. Why do transition (d-block) elements typically form coloured ions?

    They have partially filled d orbitals; d–d electronic transitions absorb visible light, and the complementary colour is transmitted/observed.

16. List four general characteristic properties of transition (d-block) metals.

    Variable oxidation states, coloured ions/compounds, catalytic activity, and formation of complex/coordination compounds (and many are paramagnetic).

17. What is the role of the blast furnace's coke and limestone in extracting iron from haematite?

    Coke (C) acts as fuel and reducing agent (forms CO, which reduces Fe₂O₃ to Fe); limestone (CaCO₃) decomposes to CaO, which combines with silica impurities to form slag (CaSiO₃).

18. Define IUPAC functional-class concepts: distinguish a homologous series.

    A homologous series is a family of organic compounds with the same general formula and functional group, where consecutive members differ by a –CH₂– unit and show a gradation in physical properties.

19. Define electrophile and nucleophile.

    An electrophile is an electron-deficient species that accepts an electron pair (e.g., H⁺, NO₂⁺); a nucleophile is an electron-rich species that donates an electron pair (e.g., OH⁻, NH₃, CN⁻).

20. State Markovnikov's rule for addition of HX to an unsymmetrical alkene.

    When HX adds to an unsymmetrical alkene, the hydrogen attaches to the carbon already bearing more hydrogen atoms, and the halogen goes to the carbon with fewer hydrogens.

21. Write the general formulas for alkanes, alkenes, and alkynes.

    Alkanes: CₙH₂ₙ₊₂ (single bonds); alkenes: CₙH₂ₙ (one C=C); alkynes: CₙH₂ₙ₋₂ (one C≡C).

22. Compare the functional groups of aldehydes, ketones, and carboxylic acids.

    Aldehyde: –CHO (carbonyl with at least one H); ketone: C=O flanked by two carbons (–CO–); carboxylic acid: –COOH (carboxyl group).

23. Which reagents distinguish an aldehyde from a ketone?

    Tollens' reagent (gives a silver mirror) and Fehling's solution (gives a red Cu₂O precipitate) are reduced by aldehydes but not by ketones.

24. Name the four major classes of biomolecules and their building-block monomers.

    Carbohydrates (monosaccharides), proteins (amino acids), lipids (fatty acids + glycerol), and nucleic acids (nucleotides).

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