Which one of the following has the lowest m.p.?
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Solution
The m.p dcreases form B to Ga ,hence gallium (Ga)has least m.p. (303 K) among group of 13 element.
Be2C and Al4C3 are called –
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Solution
Least thermally stable is –
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Solution
The thermal stability of tetrahalides decreases in order CX4 > SiX4 > GeX4 > SnX4 and in terms of same metal with different halides is in order of MF4 > MCl4 > MBr4 > MI4
The chemical name of phosgene is
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Solution
Carbonyl chloride (COCl2) is known as phosgene
Coal gas is a mixture of :
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Solution
Coal gas is a mixture of H2 + CO + N2 + CH4.
Producer gas is the mixture of :
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Solution
Producer gas is a fuel gas and is mixture of CO and N2.
The oxide of lead used in lead accumulators is :
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Solution
PbO2 is a strong oxidising agent and is produced in situ in lead storage batteries. The anode is oxidized to PbO2 and cathode is reduced to spongy Pb.
Glass reacts with HF to produce
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Solution
6HF + SiO2 ⟶ H2SiF6 + 2H2O
In graphite, electrons are
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Solution
In graphite, each carbon is sp2-hybridized and one singly occupied unhybridized p-orbitals of C-atoms overlap side wise to form a ?-electron cloud which is delocalized and thus the electrons are spread out between the structure.
Activated charcoal is employed to remove colouring matter from pure substances. It works by :
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Solution
Activated charcoal is an allotropic form of carbon made by heating or chemically oxidizing sawdust or peat. It has large surface area and acts as adsorbant.