When sulphur is heated with NaOH (aq)? The compounds formed are

Na₂S+H₂O
Na₂SO₃+H₂O
Na₂S+Na₂S₂O₃+H₂O
Na₂S₂O₃+H₂O

Solution

4S+6NaOH→Na₂S₂O₃+2Na₂S+3H₂O

A metal salt solution forms a yellow precipitate with potassium chromate in acetic acid, a white precipitate with dil H₂SO₄, but gives no precipitate with NaCl. The metal salt solution will consist of

PbCO₃
BaCO₃
MgCO₃
CaCO₃

Solution

BaCO₃ forms a yellow ppt of barium chromate. BaCO₃ forms a white precipitate of BaSO₄. BaCl₂ is soluble in water.

Which of the following has density greater than water?

Solution

Li, Na, K are lighter than water but Rb is heavier than water.

An inorganic compound which on heating first melts, then solidifies and liberates O₃ gas, the inorganic compound is

Al₂O₃
KMnO₄
MnO₂
KClO₃

Solution

Which is most basic in character ?

CsOH
KOH
NaOH
LiOH

Solution

Since the ionization energies of alkali metals decrease down the group, the ionic character and consequently basic property of their hydroxides increases in the same order,i.e. from LiOH to CsOH.

Which property of sodium is being used in street lights ?

It shows photoelectric effect
It has low melting point
Sodium atomemits photons in the yellow region ofvisible spectrum, due toelectrically stimulated transitions
Sodium vapours show golden colour

Solution

The property of sodium atom to emit photons in yellow region of visible spectrum, due to electrically stimulated electron transitions is used in street lights.

Which of the following statements is incorrect?

Alkalimetal hydroxide are hygroscopic
Dissolution of Alkali metal hydroxide is endothermic
Aqueous solution of alkali metal hydroxides arestrongly basic
Alkali metal hydroxides form ionic crystals

Solution

During the dissolution of alkali metal hydrides energy is released in large amount, i.e., it is exothermic in nature.

Which of the following does not illustrate the anomalous properties of lithium?

The melting point and boiling point of Li are comparatively high
Li is much softer than the other group I metals
Li forms a nitride Li₃ N unlike group I metals
The ion of Li and its compounds are moreheavilyhydrated than those of the rest of the group

Solution

Li is much softer than the other group I metals. Actually Li is harder then other alkalimetals

Which one of the alkaline earth metals shows some anomalous behaviour and has same electronegativity as aluminium?

Solution

Be shows diagonal relationship with Al

When potassium dichromate crystals are heated with conc.HCl

O₂ is evolved
chromyl chloride vapours are evolved
Cl₂ is evolved
no reaction takes place

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