EASY
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The basic structural unit of feldspar, zeolites mica, and asbestos is:

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Important Questions on p-Block Elements - I

MEDIUM

Correct statements among regarding silicones are:
(a) They are polymers with hydrophobic character.
(b) They are biocompatible.
(c) In general, they have high thermal stability and low dielectric strength.
(d) Usually, they are resistant to oxidation and used as greases.

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Among the following substituted silanes, the one which will give rise to cross linked silicone polymer on hydrolysis is?
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Identify the correct statements from the following:

a) Silicones are hydrophobic in nature. 

b) The repeating unit in silicones is

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c) In a C60 molecule, twenty C6 rings and twelve C5 rings are present. 

d) Dehydration of formic acid by concentrated H2SO4 at 100oC gives CO2

e) The distance between two layers in graphite is 34 pm

EASY
Identify the incorrect statements from the following
I. Tin in +2 state acts as reducing agent while lead in +4 state acts as strong oxidising agent.
II. Silicon exists as both SiF62- and SiCl62- forms.
III. The hybridisation of carbon in fullerene is sp3.
IV. Among Ge, Sn and Pb lowest melting point is for Sn.
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The gas evolved on heating CaF2 and SiO2 with concentrated H2SO4, on hydrolysis gives a white gelatinous precipitate. The precipitate is:
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Formic acid reacts with concentrated H2SO4 at 100°C to liberate A. When A is passed over heated ferric oxide, B and C are formed. What are A, B and C, respectively?
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What product is formed when HF reacts with glass?
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CH33SiCl is used during polymerization of organosilicons because
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Match the items in Column I with its main use listed in Column II:
 
  Column I   Column II
A Silica gel i. Transistor
B Silicon ii. Ion-exchanger
C Silicone iii. Drying agent
D Silicate iv. Sealant
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Identify the correct statements from the following:
(a) CO2g is used as a refrigerant for ice cream and frozen food.
(b) The structure of C60 contains twelve six-membered carbon rings and twenty-five membered carbon rings.
(c) ZSM5, a type of zeolite, is used to convert alcohols into gasoline.
(d) CO is a colourless and odourless gas.
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The major products obtained in the reaction of oxalic acid with conc. H2SO4 upon heating are
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Which of the following organo-silicon compound on hydrolysis will given a three dimensional silicon ?
MEDIUM
Si reacts with CH3Cl at 573 K in the presence of Cu powder to form methyl substituted chlorosilanes. Among the given methyl substituted chlorosilanes, whose yield is minimum?
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Zeolites are shape selective structures because of
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Example of a three-dimensional silicate is :