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Shivani siva
@shivani-siva
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Joined: Aug 6, 2021
Last seen: Sep 10, 2021
Topics: 289 / Replies: 1732
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Answer to: CaO and NaCl have the same crystal structure and approximately the same ionic radii. If U is the lattice energy of NaCl, the approximate lattice energy of CaO is

(c) 4C Explanation: Lattice energy = In NaCl the product of charges = 1 × 1; In CaO product of charges = 2 × 2 = 4 while the interionic dist...

4 years ago
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Answer to: Which of the following substances has the least ionic character?

Correct answer: (b) ZnCl2 Explanation: Polarizing power of Zn2+ is more than others, hence ZnCl2 is least ionic in nature.

4 years ago
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Answer to: The formation of molecular complex BF3 – NH3 results in a change in hybridization of boron

Correct answer: (b) from sp2 to sp3 Explanation: In BF3, B is sp2 hybridized with one empty pz orbital. The empty pz orbital of BF3 can be filled ...

4 years ago
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Answer to: In which of the following sets, all the given species are isostructural?

Correct answer: (d) BF4-, CCl4, NH4+, PCl4+ Explanation: All have tetrahedral structure.

4 years ago
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Answer to: Which of the following statements is incorrect? (a) NH3 is more basic than PH3. (b) NH3 has a higher boiling point than that of HF.

Correct answer: (b) NH3 has a higher boiling point than that of HF. Explanation: Due to high EN of F than N, H-bonding is stronger in HF than NH3 ...

4 years ago
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Answer to: KF combines with HF to form KHF2. The compound contains the species

Correct answer: (c) K+ and [HF2]- Explanation: Since F form H-bond [HF2]- exists. Therefore KHF2 gives K+ + HF2-

4 years ago
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Answer to: The true statements from the following are 1. PH5 and BiCl5 do not exist 2. pπ - dπ bond is present in SO2

Correct answer: (b) 1, 2, 5 Explanation: SeF4 has distorted tetrahedral geometry while CH4 has tetrahedral geometry.

4 years ago
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Answer to: The maximum number of 90º angles between bond pair-bond pair of electrons is observed in

Correct answer: (d) sp3d2 hybridization Explanation: figure.png sp3d2 hybridisation Number of 90° angle between bonds = 12

4 years ago
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Answer to: Which of the following statement is correct? (a) FeCl2 is more covalent than FeCl3. (b) FeCl3 is more covalent than FeCl2.

Correct answer: (b) FeCl3 is more covalent than FeCl2. Explanation: According to Fajan's rule, higher charge on the ions, more covalent is the com...

4 years ago
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Answer to: Which element is common to all acids? (b) Compounds such as alcohol and glucose also contain hydrogen but are not categorised as acids. Describe an activity to prove it.

(a) Hydrogen. (b) Activity: Take solutions of glucose, alcohol, hydrochloric acid and sulphuric acid. Fix two nails on a cork, and place the cork ...

4 years ago
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Answer to: With the help of labelled diagrams, describe an activity to show that acids produce ions only in aqueous solutions.

Activity: Take about 1g solid NaCl in a clean and dry test tube and add some concentrated sulphuric acid to it. Fit a rubber cork with a small deliv...

4 years ago
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Answer to: What happens when an acid reacts with a metal carbonate? Explain with the help of an example. Write chemical equation of the reaction involved. (b) What happens when carbon dioxide gas is passed through lime water :

(a) When an acid reacts with a metal carbonate, then a salt, carbon dioxide and water are produced. Example: When dilute hydrochloric acid reacts wi...

4 years ago
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Answer to: Why do acids not show acidic behaviour in the absence of water? (b) Why does an aqueous solution of an acid conduct electricity?

(a) The acidic behavior of an acid is due to the presence of hydrogen ions [H+(aq) ions] which are produced only when acids are dissolved in water. In...

4 years ago
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Answer to: What is produced if an acid is added to a base? (b) Why does dry HCl gas not change the colour of dry litmus paper?

(a) Salt and water. (b) Because dry HCl gas has no hydrogen ions (H+ ions) in it which can impart acidic properties to it. (c) Pink.

4 years ago
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Answer to: Why should curd and other sour foodstuffs (like lemon juice, etc.) not be kept in metal containers (such as copper and brass vessels)?

Curd and other sour substances contains acids which can react with the metals of brass and copper vessels to form toxic (poisonous) metal compounds wh...

4 years ago
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Answer to: What is a neutralisation reaction? Explain with an example. Give the chemical equation of the reaction which takes place.

The reaction between an acid and a base to form salt and water is called a neutralisation reaction. When hydrochloric acid reacts with sodium hydroxid...

4 years ago
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Answer to: Why do HCl, H2SO4, HNO3, etc., show acidic character in aqueous solutions while solutions of compounds like C6H12O6 (glucose) and C2H5OH (alcohol) do not show acidic character?

The acidic character of a substance is due to the presence of hydrogen ions [H+(aq) ions] in its aqueous solution. HCl, H2SO4 etc. show acidic propert...

4 years ago
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