NEET Questions Solved


What would you observe if excess of dilute NaOH solution is added and shaken with an aqueous solution of aluminium chloride?

(a) A permanent white precipitate is formed immediately

(b) No change at first but a white precipitate is formed on standing

(c) A white precipitate is formed which later dissolves

(d) A green precipitate which turns red on standing in air

(c)

 AlCl3 + 3NaOH          Al(OH)3 + 3NaClAl(OH)3 + 3NaOH          Na3AlO3 + 3H2O                                              soluble

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Hypo is chemically:

(a) Na2S2O3.2H2O

(b) Na2S2O3.3H2O

(c) Na2S2O3.4H2O

(d) Na2S2O3.5H2O

(d) It is chemical formula of Hypo.

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If NaOH is added to an aqueous solution of Zn2+ ions, a white precipitate appears and on adding axcess NaOH, the precepitate dissolves. In this solution zinc exists in the:

(a) cationic part

(b) anionic part

(c) both in cationic and anionic parts

(d) there is no zinc left in the solution

(b) 

Zn2+ + 2NaOH          2Na+ + Zn(OH)2Zn(OH)2 + 2NaOH         Na2ZnO2 + 2H2OThus, Na2ZnO2 forms 2 Na+ and ZnO22-ions.

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Soda lime is:

(a) Na2CO3 + CaO

(b) NaOH + NaHCO3

(c) NaOH + CaO

(d) NaH + Na2CO3

(c) Soda lime is NaOH + CaO, used for decarboxylation in organic reactions.

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Molecular formula of Glauber's salt is :

(a) MgSO4·7H2O

(b) CuSO4·5H2O

(c) FeSO4·7H2O

(d) Na2SO4·10H2O

(d) Glauber's salt is sodium sulphate decahydrate.

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Among the following, which has minimum solubility in water?

(a) KOH

(b) CsOH

(c) LiOH

(d) RbOH

(c) The solublity of hydroxides increases down the group.

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Caustic soda is:

(a) efflorescent

(b) deliquescent

(c) hygroscopic

(d) oxidant

(b) A deliquescent substance absorbs water to the extent that it forms a saturated solution.

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Pearl ash and caustic potash are chemically:

(a) K2CO3 and KOH

(b) KOH and K2CO3

(c) Na2CO3 and KOH

(d) Na2CO3 and NaOH

(a) Pearl ash is K2CO3; caustic potash is KOH.

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Tin dissolves in boiling caustic soda solution because of the formation of soluble:

(a) Sn(OH)2

(b) Sn(OH)4

(c) Na2SnO3

(d) none of these

(c) Sn + 2NaOH + H2O        Na2SnO3 + 2H2

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Which one is the highest melting point halide?

(a) NaCl

(b) NaBr

(c) NaF

(d) NaI

(c) NaF possesses most ionic character.

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