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How many grams of concentrated nitric acid solution should be used to prepare 250mL of 2 M HNO3? The concentrated acid is 70 % (w/w) HNO3 .

Given that, 2M HNO3 means 2 moles of HNO3 in 1000mL of solution. Therefore, in 250mL solution we have 2/1000 × 250 = 0.5moles Molecular weight... View Article

Which of the following is the strongest base?

a) b) c) Answer: (c) Benzyl amine In acid-base reactions, strong bases are those that can remove a proton from a very weak acid, such... View Article

Acidic hydrogen is present in: A. Ethyne B. Ethene C. Benzene D. Ethane

Answer: a) Ethyne It appears that acidic hydrogen is released as the H+ ion. As a result, any H-atom bonded to another atom or group of atoms... View Article

What is the packing efficiency of bcc?

Body centred cubic unit cell- Here, the atoms are present at the corners of the cube and also one in the centre of the cube. Thus, there are two... View Article

Geometric representation of age structure is a characteristic of :

Geometric representation of age structure is a characteristic of population Population A discrete assemblage of entities with... View Article

Which of the following molecules have zero dipole moment? (a) NH3 (b)H2O (c)BeF2 (d)SO2

The correct answer is (c)BeF2 In a beryllium fluoride molecule, the bond angle between the two beryllium-fluorine bonds is 180o.... View Article

Statement – I: An electric dipole is placed at the centre of a hollow sphere. The flux of the electric field through the sphere is zero but the electric field is not zero anywhere in the sphere. Statement – II: If R is the radius of a solid metallic sphere and Q be the total charge on it. The electric field at any point on the spherical surface of radius r (< R) is zero but the electric flux passing through this closed spherical surface of radius r is not zero. In the light of the above statements Choose the correct answer from the option given below: a. Statement I is true but Statement II is false b. Statement I is false but Statement II is true c. Both Statement I and Statement II are true d. Both Statement I and Statement II are false

The correct answer is a. Statement I is true but Statement II is false According to Gauss's law, electric flux depends only on the charge... View Article

A conducting rod PQ of length 4ℓ is rotated about a point O in a uniform magnetic field B. PO = ℓ Then (a) VQ – VP = – [{Bωℓ²} / {2}] (b) VQ – VO = (5/2) Bωℓ² (c) VQ – VO = (9/2) Bωℓ² (d) VP – VQ = 4 Bωℓ²

As per the diagram Let us assume Potential difference between point O & P is VO – VP . Potential difference... View Article

A common emitter amplifier is designed with n-p-n transistor (α=0.99). The input impedence is 1kΩ and load is 10kΩ. The voltage gain will be (a) 9900 (b) 99 (c) 9.9 (d) 990

The correct answer is (d) 990 The NPN transistor consists of two n-type semiconductors that sandwich a p-type semiconductor. Here,... View Article

At low pressure, the van der Waal’s equation is reduced to

At low pressure, the van der Waal's equation is reduced to Van der Waals equation is an equation relating the relationship between the... View Article

A simple pendulum is oscillating without damping. When the displacement of the bob is less than maximum, its acceleration vector a is correctly shown in

To find the acceleration of the pendulum, firstly calculate the time taken for one oscillation (T) by the pendulum by dividing the total time by... View Article

Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure of a mixture of 26.0 g of heptane and 35 g of octane?

Vapour pressure of heptanes, = 105.2 kPa Vapour pressure of octane, = 46.8 kPa We know that, Molar mass of heptanes (C7H16) = 7 x... View Article

Which of the following statements in relation to the hydrogen atom is correct? (a) 3s, 3p and 3d orbitals all have the same energy (b) 3s and 3p orbitals are of lower energy than 3d orbital (c) 3p orbital is lower in energy than 3d orbital (d) 3s orbital is lower in energy than 3p orbital

The correct answer is (d) 3s orbital is lower in energy than 3p orbital In a hydrogen atom, 3s,3p and 3d orbitals will have same energy. In... View Article

A ball moving with velocity 2m/s collides head on with another stationary ball of double the mass. If the coefficient of restitution is 0.5, then their velocities (inm/s) after collision will be (a) 0,1 (b) 1,1 (c) 1, 0.5 (d) 0,2

The correct answer is (a) 0,1 As per the given data m1 = m, m2 = 2m u1= 2 m/s u2 = 0 Coefficient of restitution, e = 0.5 Find... View Article

A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 second respectively. The length of the train is. (1) 45 metres (2) 40 metres (3) 54 metres (4) 50 metres

The correct answer is (4) 50 metres Let the length of train be x km Let the speed of the train be y km/hr 2 kmph = (2 x 5/18) m/sec =... View Article

The electrons identified by quantum numbers n and l, (i) n=4,l=1, (ii) n=4,l=0 (iii) n=3,l=2 and (iv) n=3,l=1 can be placed in order of increasing energy as (a) (i) < (ii) < (iii) < (iv) (b) (iv) < (iii) < (ii) < (i) (c) (iv) < (ii) < (iii) < (i) (d) (iv) < (i) < (ii) < (iii)

The correct answer is (c) (iv) < (ii) < (iii) < (i) Solution The greater is the value of (n+l), the greater is the energy... View Article

What is number system?

A number system is defined as a system of writing to express numbers. It is the mathematical notation for representing numbers of a given set by... View Article

In a town of 10,000 families, it was found that 40% of the families buy newspaper A, 20% buy newspaper B, 10% buy newspaper C, 5% buy A and B; 3% buy B and C, and 4% buy A and C. IF 2% buy all the three newspapers, find the number of families which buy (i) A only, (ii) B only, (iii) none of A, B, and C.

Given Total number of families = 10000 Percentage of families that buy newspaper A = 40 Percentage of families that buy newspaper B = 20... View Article

Lattice energy of an ionic compound depends upon (a) charge on the ion only (b) size of the ion only (c) packing of the ion only (d) charge and size of the ion.

The correct answer is (d) charge and size of the ion. Lattice energy can be defined as the energy required to convert one mole of an... View Article

Cyanide process is used in the extraction of (a) gold (b) silver (c) both of these (d) none of these

The correct answer is (c) both of these The cyanide process is used for the extraction of Au and Ag from their ores by dissolving them in a... View Article

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