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The p-Block Elements

Short Answer Type

151.

Why dilute H₂SO₄ cannot be used for the laboratory preparation of carbon dioxide?

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152.

Why is it dangerous to sleep in a closed room in which coal is burning ?

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153.

Explain the following phenomenon by means of balanced equations:
(i) When exhaling is made through a tube passing into a solution of lime water, solution becomes turgid.
(ii) The turbidity of the above solution.
(iii) eventually disappears when continued exhaling is made through it.

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154.

What is dry ice? Why is it so called?

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155. Suggest a reason as to why CO is poisonous.

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156.

How is excessive content of CO₂responsible for global warming?

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157.

Write the resonance structures of $CO subscript 3 superscript 2 minus end superscript space and space HCO subscript 3 superscript minus$

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158.

What is the state of hybridization of carbon in (a) $CO subscript 3 superscript 2 minus end superscript$ (b) diamond (c) graphite?

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Long Answer Type

159.
Explain why silicon tetrachloride is hydrolyzed but carbon tetrachloride is not hydrolysed.

CCl₄ is not hydrolysed by water because carbon has no d-orbitals and hence cannot expand its coordination number beyond 4. However, silicon atom of silicon tetrachloride has energetically suitable vacant d-orbitals. Thus, it can accept a lone pair of electrons from oxygen atom of a water molecule. Therefore, silicon atom can expand its coordination number beyond four. Due to this reason SiCl₄ is hydrolysed.