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If Z is the number of atoms in the unit cell that represents the closest packing sequence ABCABC, the number of tetrahedral voids in the unit cell is equal to:

Answer: 2Z Explanation The number of tetrahedral voids in closed packed ccp, fcc, and hcp is double the number of... View Article

Explain biuret test for protein

Biuret is a chemical made by heating urea to 180 degrees Celsius. The Biuret test is a chemical test that... View Article

Four metallic plates each with a surface area of one side A, are placed at a distance d from each other. The two outer plates are connected to one point A and the two other inner plates to another point B . Then the capacitance of the system is

Applying Gauss’s law to this closed surface, we get, ∮E.ΔA=Qen/ε0=σΔA/ε0 ⇒ EΔA =σΔA/ε0 ⇒ E = σ/ε0 = Q/Aε0 Now,... View Article

The most stable free radical among the following is (1)C6H5CH2C˙H2(2)C6H5C˙HCH3(3)CH3C˙HCH3(4)C˙6H5

Answer: (2)C6H5C˙HCH3 Explanation We know that a radical’s stability is determined by its intrinsic energy. If the radical’s internal energy... View Article

Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers, l = 1 and 2 are, respectively:

There are four quantum numbers that we are all familiar with: The size of the electron cloud and the energy... View Article

Which of the following will not give an iodoform test? A. Ethanal B. Ethanol C. 2 – propanone D. 3 – pentanone

Answer:(D) 3 – pentanone Explanation The iodoform test is used to evaluate whether a carbonyl compound with the formula CH3C=O... View Article

Which will make the basic buffer? A) 50 mL of 0⋅1 M NaOH + 25 mL of 0⋅1M CH3COOH B) 100 mL of 0⋅1 M CH3COOH + 100 mL of 0⋅1M NaOH C) 100 mL of 0⋅1 M HCl + 200 mL of 0⋅1M NH4OH D) 100 mL of 0⋅1 M HCl + 100 mL of 0⋅1M NaOH

Answer: (c) 100 mL of 0⋅1 M HCl + 200 mL of 0⋅1M NH4OH Explanation We’ll start by learning about... View Article

The most reactive element in the halogen group is …………. A. Astatine B. Iodine C. Chlorine D. Fluorine

Answer: Fluorine Explanation On the periodic table, the halogens are to the left of the noble gases. Fluorine (F), chlorine... View Article

A compound is formed by cation C and anion A. The anions form hexagonal close packed (HCP) lattice and the actions occupy 75% of octahedral voids. What is the formula of the compound?

Answer: C3A4 Explanation In hexagonal close packed (HCP) lattice, the number of atoms = 6 The number of atoms is... View Article

The rate of a first order reaction is 0.04 molL⁻¹s⁻¹ at 10 seconds and 0.03 molL⁻¹s⁻¹ at 20 seconds after initiation of the reaction. What is the half-life period of the reaction?

We know that for a first-order reaction – K = 2.303/t2−t1.log[A]1/[A]2 Here, t2 = final time; [A]2 = final concentration... View Article

What is the maximum spin multiplicity for 4d-orbital? (a).4 (b).6 (c).5 (d).0

Answer: (b) 6 Explanation For the same spatial electronic wave-function, spin multiplicity is the number of possible orientations of the... View Article

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... View Article

Which of the following is the strongest base?

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

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

Answer: a) Ethyne Explanation It appears that acidic hydrogen is released as the H+ ion. As a result, any H-atom... 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... View Article

Geometric representation of age structure is a characteristic of :

Geometric representation of age structure is a characteristic of population Solution Population A discrete assemblage of entities with identifiable characteristics... 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 Dipole moment of BeF2 In a beryllium fluoride molecule, the bond angle between the two beryllium-fluorine bonds... 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 Solution According to Gauss’s law, electric... 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 between... 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 Solution The NPN transistor consists of two n-type semiconductors that sandwich a p-type semiconductor.... View Article

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