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Prisha Laxmi
@prisha-laxmi
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Joined: Mar 13, 2022
Last seen: May 1, 2022
Topics: 0 / Replies: 163
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Answer to: What are inner transition elements? Decide which of the following atomic numbers are the atomic numbers of the inner transition elements: 29, 59, 74, 95, 102, 104.

Inner transition metals are those elements in which the last electron enters the f-orbital. The elements in which the 4f and the 5f orbitals are progr...

3 years ago
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Answer to: What are alloys? Name an important alloy which contains some of the lanthanoid metals. Mention its uses.

An alloy is a solid solution of two or more elements in a metallic matrix. It can either be a partial solid solution or a complete solid solution. All...

3 years ago
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Answer to: Indicate the steps in the preparation of: (i) K2Cr2O7 from chromite ore. (ii) KMnO4 from pyrolusite ore.

(i) Potassium dichromate (K2Cr2O7) is prepared from chromite ore (FeCr2O4) in the following steps. Step (1): Preparation of sodium chromate FeCr2O...

3 years ago
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Answer to: Give examples and suggest reasons for the following features of the transition metal chemistry: (i)The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.

(i) In the case of a lower oxide of a transition metal, the metal atom has a low oxidation state. This means that some of the valence electrons of the...

3 years ago
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Answer to: Calculate the number of unpaired electrons in the following gaseous ions: Mn^3+, Cr^3+, V^3+ and Ti^3+. Which one of these is the most stable in aqueous solution?

(i) Mn3+, [Ar]3d4 → 4 (ii) Cr3+, [Ar]3d3 → 3 (iii) V3+, [Ar]3d2 → 2 (iv) Ti3+, [Ar]3d1 → 1 Cr3+ is the most stable in aqueous solutions owing ...

3 years ago
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Answer to: Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?

In the first transition series, Cu exhibits +1 oxidation state very frequently. It is because Cu (+1) has an electronic configuration of [Ar] 3d10. Th...

3 years ago
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Answer to: What is meant by 'disproportionation'? Give two examples of disproportionation reaction in aqueous solution.

It is found that sometimes a relatively less stable oxidation state undergoes an oxidation - reduction reaction in which it is simultaneously oxidised...

3 years ago
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Answer to: How would you account for the following: (i) Of the d^4 species, Cr^2+ is strongly reducing while manganese(III) is strongly oxidising.

(i) Cr2+ is strongly reducing in nature. It has a d4 configuration. While acting as a reducing agent, it gets oxidized to Cr3+ (electronic configurati...

3 years ago
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Answer to: Compare the chemistry of actinoids with that of the lanthanoids with special reference to:

(i) Electronic configuration: The general electronic configuration for lanthanoids is [Xe]54 4f0-14 5d0-16s2 and that for actinoids is [Rn]86 5f1-146d...

3 years ago
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Answer to: Which one of the following statements is not true? (a) pH of drinking water should be between 5.5 – 9.5. (b) Concentration of DO below 6 ppm is good for the growth of fish.

Correct answer: (b) Concentration of DO below 6 ppm is good for the growth of fish. Explanation: The ideal value of DO for growth of fishes is 8 m...

3 years ago
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Answer to: Which of the following is/are formed when ozone reacts with the unburnt hydrocarbons in polluted air?

Correct answer: (d) (i), (ii) and (iii) Explanation: 3CH4 + 2O3 → 3CH2 = O + 3H2O CH2 = CHCH = O; CH3COONO2

3 years ago
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Answer to: Which of the following statement(s) is/are true about waste recycling? (i) Clothes can be made from recycled plastic waste.

Correct answer: (d) All of these Explanation: All the given statements are true for about waste recycling.

3 years ago
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Answer to: Which of the following practices will not come under green chemistry?

Correct answer: (d) Using plastic cans for storing substances

3 years ago
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Answer to: Which of the following statements are not correct? (i) F^- ion concentration above 2 ppm causes brown mottling in teeth.

Correct answer: (d) (iii) and (iv) Explanation: For statement (iii), Methemoglobinemia (blue baby syndrome) is caused due to excess of nitrate in ...

3 years ago
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Answer to: Which one of the following pairs is mismatched (a) Fossil fuel burning → release of CO2 (b) Nuclear power → radioactive wastes

Correct answer: (c) Solar energy → Green house effect Explanation: Solar energy is not responsible for green house effect instead it is a source o...

3 years ago
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Answer to: Lichens do not like to grow in cities (a) because of absence of the right type of algae and fungi

Correct answer: (c) because of SO2 pollution Explanation: Because lichens are very sensitive to sulphur dioxide and in cities the amount of SO2 is...

3 years ago
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