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Why is the thermos flask covered with a cork stopper? Give reason.

Solution: The lid of the thermos flask is covered with a tight cork stopper to minimise the heat loss by convection so that convection currents... View Article

The dipole moment of H2O is 1.85D.HOH angle is 105°. O-H bond length is 0.94A˚. The magnitude of charge-separated on the oxygen atom is (cos 52.5° − 0.61)

(A) 1/2 of the magnitude of the charge on the electron (B) 1/3 of the magnitude of the charge on the electron (C) 1/4 of the magnitude of the... View Article

Which of the following elements has the same oxidation state in all of its compounds?

(A) Carbon (B) Oxygen (C) Fluorine (D) Hydrogen The Correct Answer is (C) Fluorine. Solution: Fluorine(F) shows a single oxidation... View Article

Which of the following compounds has pseudo inert gas configuration?

(A) K+ (B) S2- (C) Na+ (D) Cu+ The Correct Answer is (D) Cu+. Solution: An element with a pseudo noble gas configuration has 18 electrons... View Article

As the quantum number increases, the difference of energy between conservative energy levels____.

(A) Increases (B) Decreases (C) Remains the same (D) Increases and then decreases. The Correct Answer is (B) Decreases. Solution: As the... View Article

0.25 g lyophilic colloid is added to 100 ml gold solution to prevent the coagulation from adding 1 ml 10% NaCl solution. What will be a gold number of lyophilic colloids?

(A) 25 (B) 125 (C) 250 (D) 0.25 The Correct Answer is (A) 25. Solution: As given in the question, 0.25 g lyophilic colloid is added... View Article

Which of these elements of the 2nd period forms the strongest acidic oxide?

(A) Boron (B) Carbon (C) Nitrogen (D) Fluorine The Correct Answer is (D) Fluorine. Solution: Among the given elements of the 2nd period,... View Article

Which of the following molecules has non – dipole moment?

(A) NH+4 (B) PCl5 (C) BrF3 (D) XeO3F2 The Correct Answer is (C) BrF3 Bromine trifluoride (BrF3) molecule has a non-dipole moment. This... View Article

The correct order of density of the following elements is:(Be, Mg, Ca, Sr)?

(A) Be > Mg > Ca > Sr (B) Ca > Mg > Be > Sr (C) Mg < Ca < Sr < Be (D) Ca < Mg < Be < Sr The Correct... View Article

Which of the following is the incorrect order of dipole moment?

(A) HF > HCl > HBr (B) NH3 > NCl3 > NF3 (C) NH3 > NF3 > NCl3 (D) CH3Cl > CH3F > CH3Br The Correct Answer is (C) NH3... View Article

Which one of the following is the incorrect order of boiling points of the alkyl/aryl halides?

(A) CHCl3 > CH2Cl2 (B) (CH3)3CCL > (CH3)2CHCH2Cl (C) CH3 (CH2)3 Cl > CH3 (CH2)2 Cl (D) CH3 (CH2)3 Cl > CH3CH2CHCICH3 The Correct... View Article

Which of the following elements has the highest electron affinity?

(A) Oxygen (B) Chlorine (C) Nitrogen (D) Fluorine The Correct Answer is (B) Chlorine. Solution: Among the following elements, chlorine has... View Article

Assertion: Sodium hydrogen-carbonate is an acidic salt. Reason: The pH of an aqueous solution of sodium hydrogen-carbonate is more than 7.0.

(A) Assertion is true and the reason is false. (B) Assertion is false and the reason is true. (C) Both Assertion and Reason are true. The... View Article

Mechanism of a hypothetical reaction X2 + Y2 → 2xy is given below.(i) X2 ⇌ X + X (fast)(ii) X + Y2 → XY + Y (slow)(iii) X + Y → XY (fast)What will be the overall order of the reaction?

(A) 0 (B) 1 (C) 2 (D) 1.5 The Correct Answer is (D) 1.5. Solution: Let the above-given reaction (i) and (iii) be equilibrium reactions.... View Article

2H2S + SO2 → 2H2O + 3S. In the following reaction, what is the magnitude of difference in the oxidation state of sulphur in H2S and in SO2?

(A) 0, +2 (B) -4, 0 (C) -2, +2 (D) +2, -4 The Correct Answer is (D) +2, -4. Solution: The oxidation state of S changes from -2 in H2S... View Article

When F2 reacts with H2S, Sulphur’s product (x) is formed.

(A) SF2 (B) SF4 (C) SF6 (D) OF2 The Correct Answer is (C) SF6 Solution: When Hydrogen Sulfide (H2S) reacts with Fluorine (F2), the compound... View Article

A greenish coating that develops on copper utensils is due to the formation of

(A) CuO (B) CuCO3 (C) Cu(OH)2 (D) Cu(OH)2.CuCO3 The Correct Answer is (D) Cu(OH)2.CuCO3. Solution: All copper vessels develop a green... View Article

An electron is moving in the 3rd orbit of Li2+ and its separation energy is y. The separation energy of an electron moving in the 2nd orbit of He+ is:

(A) y (B) (C) (D) The Correct Answer is (A) y Solution: As given: The separation energy of Li2+ is y Then Therefore, y = 13.6... View Article

Identify A and B in the following reaction.

Solution: In this reaction, Mg will exist as Mg2+, and it will attack chlorine since it has more electron density. This will be a... View Article

Generally, transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds are expected to be coloured in solid-state?

(A) CuF2 (B) ZnF2 (C) Cu2Cl2 (D) Ag2SO4 The Correct Answer is (A) CuF2. Solution: Transition elements form coloured salts due to the... View Article

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