The S-block Elements

Match List- I with List-II

List -I
(a) Li
(b) Na
(c) KOH
(d) Cs

List-II
(i) absorbent for carbon dioxide
(ii) electrochemical cells
(iii) coolant in fast breeder reactors
(iv) photoelectric cell

Choose the correct answer from the options given below:

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Contributor-Level 10

Li is used in making batteries, liquid Na is a coolant in nuclear reactors. Cs is used in photoelectric cells and KOH as a base is used to absorb acidic oxides like CO?

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2 months ago

Identify the incorrect statement from the following

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Contributor-Level 10

The oxidation state of K in KO? is (+1).

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2 months ago

Given below are two statements:

Statement I : Both CaCl2.6H2O and MgCl2.8H2O undergo dehydration on heating.

Statement II : BeO is amphoteric whereas the oxides of other elements in the same

group are acidic.

In the light of the above statements, choose the correct answer from the options given below:

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Contributor-Level 9

Hydrated halides of group 2 from Ca onwards undergo dehydration on heating. But the hydrated halide of Mg, i.e., MgCl? ·8H? O, does not undergo dehydration on heating but undergoes hydrolysis.
BeO is amphoteric, while other oxides of group 2 are basic in nature.

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2 months ago

Match List – I with List – II:
| List – I | List – II |
| :--- | :--- |
| (a) Be | (i) Treatment of cancer |
| (b) Mg | (ii) Extraction of metals |
| (c) Ca | (iii) Incendiary bombs and signals |
| (d) Ra | (iv) Windows of X-ray tubes |
| | (v) Bearings for motor engines. |

Choose the most appropriate answer from the option given below:

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Contributor-Level 9

Be is used in X ray tube windows.
Mg is used in incendiary bombs & signals.
Compounds of Ca i.e CaCO? is used in extraction of metals like Fe.
Radium (Ra) is used in treatment of cancer in radiotherapy.

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2 months ago

The correct order of conductivity of ions in water is:

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Contributor-Level 10

In an aqueous medium, all alkali metal cations are converted into their hydrated form. More intensely positive cations have more hydration, and hence the size of the cation increases after hydration. Therefore, the Li? cation has a larger size in hydrated form and the least conductivity. The order of conductivity of alkali metal ions is: Li? < Na? < K? < Rb? < Cs?

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2 months ago

An alkaline earth metal ' M' readily forms water soluble sulphate and water insoluble hydroxide. Its oxide MO is very stable to heat and does not have rock-salt structure. M is:

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Contributor-Level 10

BeO is hexagonal wurtzite type structure.

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2 months ago

On combustion of Li, Na and K in excess of air, the major oxides formed, respectively, are:

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Contributor-Level 9

4Li + O? → 2Li? O oxide
2Na + O? → Na? O? peroxide
K + O? → KO? superoxide

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2 months ago

Two elements A and B have similar chemical properties. They don't form solid hydrogencarbonates, but react with nitrogen to form nitrides. A and B, respectively, are:

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alok kumar singh

Contributor-Level 10

Li and Mg form nitrides and have bicarbonates that are unstable

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2 months ago

Given below are two statements:
Statement I: None of the alkaline earth metal hydroxides dissolves in alkali.
Statement II: Solubility of alkaline earth metal hydroxides in water increases down the group.
In the light of the above statements, choose the most appropriate answer from the options given below:

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Contributor-Level 9

Solubility of 2 group hydroxide increases down the group.

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2 months ago

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Lithium halides are some what covalent is nature.
Reason R: Lithium possess high polarisation capability.
In the light of the above statements, choose the most appropriate answer from the options given below:

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