Blue colour of the solution of alkali metal in ammonia is due to the presence of-

1. M-atoms                                         

2. M+ ions 

3. Solvated anions                             

4. Solvated electrons

Subtopic:  Chemical Properties |
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The compound X on heating gives a colourless gas. The residue is dissolved in water to obtain Y. Excess of CO2 is bubbled through aqueous solution of Y, Z is formed. Z on gentle heating gives back X. The compound X is-

(1) CaCO3                                           

(2) Na2CO3

(3) CaSO4.2H2O                                 

(4) K2CO3

Subtopic:  Compounds of Ca and Na -Preparations, Properties & Uses |
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Assertion : s-block elements do not occur free in nature

Reason :  s-block elements are highly electropositive in nature.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  Physical Properties |
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The cation of alkali metals are found as M(H2O)+n in H2O, value of 'n' is maximum for

1. Na+

2. K+

3. Rb+

4. Li+

Subtopic:  Reasoning Questions |
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1 mole of substance (X) was treated with an excess of water. 2 moles of readily combustible gas were produced along with solution which when reacted with CO2 gas produced a white turbidity. The substance (X) could be

(1) Ca

(2) CaH2

(3) Ca(OH)2

(4) Ca(NO3)2

Subtopic:  Chemical Properties |
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A chloride dissolves appreciably in cold water. When placed on a Pt-wire in Bunsen flame, no distinctive colour is noticed. Cation present is

(1) Mg2+

(2) Ba2+

(3) Pb2+

(4) Ca2+

Subtopic:  Physical Properties |
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The fire extinguisher contains NaHCO3 and the compound (X). The compound (X) maybe -

1. CH3COOH

2. NaOH

3. C6H5OH

4. None of the above. 

Subtopic:  Chemical Properties |
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Alkali metals do not form nitride on reaction with N2, whereas lithium forms Li3N, because

(1) High ionisation energy of Li

(2) High lattice energy of Li3N

(3) High sublimation energy of Li

(4) High covalent nature of Li3N

Subtopic:  Physical Properties |
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All group-2 metals dissolve in liquid ammonia to produce a bright blue colour. The colour is due to-

1. A change in the structure of ammonia.

2. d-d transition.

3. The spectrum of the solvated electrons.

4. An electronic transition from a lower to a higher energy state.

Subtopic:  Physical Properties |
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Hsolution is positive for

I. LiF

II. CsI

III. RbF

IV. KF

(1) I, II, III & IV

(2) II only

(3) I only

(4) I & II only

Subtopic:  Chemical Properties |
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