Chemistry 11 past paper 2023

The volume occupied by $3.01 \times 10^{23}$ molecules of $NH_3$ gas at **STP** is:

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Calculate the mass of $NH_3$ gas produced when $8 dm^3$ of $H_2$ gas is reacted with excess of $N_2$ gas: $N_2 + 3H_2 \rightarrow 2NH_3$

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$100 \text{ g}$ $Zn$ is reacted with $100 \text{ g}$ solution of $HCl$: $Zn + 2HCl \rightarrow ZnCl_2 + H_2$. (i) How much volume of $H_2$ gas is released at STP? (ii) Also determi…

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Lyman series of spectral lines lies in which of the following region of electromagnetic spectrum?

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How much energy is required to remove an electron from the 1st orbit of Li²⁺ ion in the units of J/atom and kJ/mol?

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Derive a relationship for energy released ($\Delta E$) when an electron drops from $n_2$ orbit to $n_1$ orbit in $He^+$ ion. Also calculate $\Delta E$ if $n_1=1$ and $n_2=3$ in $He…

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Which of the following molecules does **not** possess trigonal planar geometry?

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Write down the disadvantages of valence bond theory.

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What is **salt hydrolysis**? Which type of cations and anions undergo hydrolysis? Describe the hydrolysis of four types of salts giving one example for each.

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Which of the following aromatic compounds has **zero dipole moment**?

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Describe any two factors which affect bond length. Give one example for each.

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What is **collision theory**? Describe with reference to the energy of activation, formation of activated complex and heat of reaction.

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The value of general gas constant $R$ is $62.4$. Its units are:

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Describe the geometries of following molecules on the basis of **VSEPR theory**: (a) $SO_3$ (b) $PCl_3$

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State and explain Dalton's law of partial pressure. Derive a relationship between: (i) Partial pressure and number of moles (ii) Partial pressure and mole fraction.

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Rate of diffusion of $H_2$ gas ($r_{H_2}$) as compared to that of $He$ gas ($r_{He}$) is:

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What is an **Isobar**? Draw an isobar for a given mass of an ideal gas at 1 atm. How does the position of isobar change with increase in pressure?

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Describe the effect of stated change on the following reactions at equilibrium position: (i) Decreasing the volume in $2NO + O_2 \rightleftharpoons 2NO_2$ (ii) Increasing temperatu…

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At $145^{\circ}C$, **Cholesteryl Benzoate** exists as:

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How are **London dispersion forces** developed in a sample of Helium gas?

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The increase in boiling point of hydrides of group IV-A ($CH_4$ to $SnH_4$) is due to increase in the strength of:

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Which substance in each of the following pairs has stronger London dispersion forces? Give reasons: (a) Ar or Kr (b) Br₂ or I₂ (c) C₂H₆ or C₄H₁₀

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Which of the following is **NOT** an anisotropic property?

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What is the role of **hydrogen bonding** in: (a) Cleansing action of soap (b) Structure of DNA and protein molecules

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Identify the pair of substances which are **not isomorphs**?

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Describe **transition temperature** by giving two examples.

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The value of $K_p$ will become equal to $K_c$, $K_x$ and $K_n$, when:

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Differentiate between **Hexagonal close packing** and **cubic close packing** in the structure of metals.

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What is a **precipitation reaction**? How can one predict the formation of precipitates of $CaF_2$ in the following reaction? $Ca^{+2} + 2F^- \rightleftharpoons CaF_2$

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For which of the following reaction, the **rate constant** is equal to the **rate of reaction**?

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How does an acetic acid/sodium acetate buffer resist change in pH on addition of NaOH?

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Boiling point of a solution prepared by dissolving 18 g glucose in 1 kg water is (Kb = 0.52):

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Why does the vapour pressure of a solvent decrease when a non-volatile, non-electrolyte solute is dissolved in it?

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A colloid in which a liquid is dispersed into another liquid is called:

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What is **reverse osmosis**? Give its one application.

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Heat capacity of a substance is measured in the units of:

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If conc. of $O_3$ in the atmosphere reaches $0.5$ ppb, what mass of $O_3$ would be present per kg of the air?

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Calculate $\Delta H^{\circ}$ for the following reaction: $2C_8H_{18} + 25O_2 \rightarrow 16CO_2 + 18H_2O$. The values of $\Delta H_f^{\circ}$ for $C_8H_{18}$, $O_2$, $CO_2$ and $H_…

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When $1.8 \text{ g}$ glucose is burnt in a bomb calorimeter, the temperature of water increases from $25^{\circ}C$ to $31.52^{\circ}C$. If the heat capacity of the calorimeter is $…

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Predict $E^{\circ}_{cell}$ for $Zn-Ni$ cell and write its cell reactions. The values of reduction potential of $Zn$ and $Ni$ are: $E^{\circ}_{Zn} = -0.76 V$ and $E^{\circ}_{Ni} = -…

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Balance the equation by **ion-electron method**: $BrO_3^{-} + SO_2 \rightarrow HSO_4^{-} + Br^{-}$

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