List of practice Questions

The equilibrium constant for a reaction is \(10\). What will be the value of \(∆G^Θ\)?
\(R= 8.314\ JK^{-1} mol^{-1}, T=300\ K\)

The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, -890.3 kJ mol^-1, -393.5 kJ mol^-1, and -285.8 kJ mol^-1 respectively. Enthalpy of formation of CH₄(g) will be

Comment on the thermodynamic stability of \(NO(g)\), given
\(\frac 12N_2(g) +\frac 12O_2(g)→NO(g); \ \ \ \ ∆_rH^Θ= 90\ kJ mol^{-1}\)
\(NO(g) +\frac 12 O_2(g)→NO_2(g);\ \ \  ∆_rH^Θ= –74\ kJ mol^{-1}\)

Calculate the entropy change in surroundings when \(1.00\ mol\) of \(H_2O(l)\) is formed under standard conditions. \(∆_fH^Θ= –286\ kJ mol^{-1}\).

Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms? Illustrate your answer by taking one example

Discuss the chemistry of Lassaigne’s test.

Determine the molecular formula of an oxide of iron, in which the mass per cent of iron and oxygen are 69.9 and 30.1, respectively.

Explain the principle of paper chromatography.

Which of the following carbocation is most stable?

What are the oxidation numbers of the underlined elements in each of the following and how do you rationalise your results? 
(a) KI₃ (b) H₂S₄O₆ (c) Fe₃O₄ (d) CH₃CH₂OH (e) CH₃COOH

Match the following prefixes with their multiples:

S.No	Prefixes	Multiples
(i)	micro	106
(ii)	deca	109
(iii)	mega	10–6
(iv)	giga	10–15
(v)	femto	10

The solubility product constant of Ag₂CrO₄ and AgBr are 1.1×10^–12 and 5.0×10^–13 respectively. Calculate the ratio of the molarities of their saturated solutions.

What sorts of information can you draw from the following reaction?
(CN)₂( g)+2OH⁻(aq)\(\rightarrow\)CN⁻(2aq)+CNO⁻(aq)+H₂O(l)

Using the standard electrode potentials given below ,predict if the reaction between the following is feasible:
(a) Fe³⁺(aq) and I^- (aq) 
(b) Ag⁺ (aq) and Cu(s)
(c) Fe³⁺ (aq) and Cu(s) 
(d) Ag(s) and Fe³⁺(aq)
(e) Br₂(aq) and Fe²⁺(aq)

The ionization constant of benzoic acid is 6.46 × 10^–5 and K_sp for silver benzoate is 2.5 × 10^–13. How many times is silver benzoate more soluble in a buffer of pH 3.19 compared to its solubility in pure water?

We have carefully distinguished between average speed and magnitude of average velocity. No such distinction is necessary when we consider instantaneous speed and magnitude of velocity. The instantaneous speed is always equal to the magnitude of instantaneous velocity. Why?

Briefly describe the structure of the Brain.

Draw labelled diagrams of the following: 

1. Neuron 
2. Brain

i and j are unit vectors along x- and y- axis respectively. What is the magnitude and direction of the vectors i+j and i-j ? What are the components of a vector A= 2 i + 3 j along the directions of i + j + and i - j ? [You may use graphical method]

Figure 11.10 shows the effect of light on the rate of photosynthesis. Based on the graph, answer the following questions: 

1. At which point/s (A, B or C) in the curve is light a limiting factor? 
2. What could be the limiting factor/s in region A? 
3. What do C and D represent on the curve?

Give comparison between the following: 

1. C₃ and C₄ pathways 
2. Cyclic and non-cyclic photophosphorylation 
3. Anatomy of leaf in C₃ and C₄ plants

A body of mass 5 kg is acted upon by two perpendicular forces 8 N and 6 N. Give the magnitude and direction of the acceleration of the body.

Explain the following processes:

1. Polarisation of the membrane of a nerve fiber
2. Depolarisation of the membrane of a nerve fiber
3. Transmission of a nerve impulse across a chemical synapse.

Differentiate between: 

1. Myelinated and non-myelinated axons 
2. Dendrites and axons 
3. Thalamus and Hypothalamus 
4. Cerebrum and Cerebellum

A brass wire 1.8 m long at 27 °C is held taut with little tension between two rigid supports. If the wire is cooled to a temperature of –39 °C, what is the tension developed in the wire, if its diameter is 2.0 mm? Co-efficient of linear expansion of brass = 2.0 × 10^–5 K^–1; Young’s modulus of brass = 0.91 × 10¹¹ Pa.