Importance of carbon - class-VIII

Question 1 Multiple Choice (Single Answer)

The tetrahedral structure of carbon was proposed by__________.

Kekule
Wohler
Vant Hoff and Le-Bel
Berthlot

Question 2 Multiple Choice (Single Answer)

All allotropes of carbon exist in ___________ state at room temperature.

liquid
solid
gas
plasma

Question 3 Multiple Choice (Single Answer)

How many triple covalent bonds can a single carbon atom form at a time?

3
2
1.5
1

Question 4 Multiple Choice (Single Answer)

How many double covalent bonds can a single carbon atom form at a time?

1
2
3
4

Question 5 Multiple Choice (Single Answer)

The oxidation state of carbon in carbon monoxide is:

$+2$
$+4$
$+3$
$-4$

Question 6 Multiple Choice (Single Answer)

Which of the following is not a source of carbon?

limestone
dolomite
calcite
haemetite

Question 7 Multiple Choice (Single Answer)

Which symbol is used for the element carbon?

$C$
$Ca$
$Cn$
$Co$
$Cu$

Question 8 Multiple Choice (Single Answer)

Compound with maximum number of $\sigma$-bond:

$CH _3CH _2CH _3$
$CH _3OH$
$C _6H _6$
$C _6H _5CH _3$
$C _6H _5C _2H _5$

Question 9 Multiple Choice (Single Answer)

Carbon has zero oxidation number in

$CH _{4}$
$\mathrm { CH } _ { 3 } \mathrm { Cl}$
$C C l _ { 4 }$
$\mathrm { CH } _ { 2 } \mathrm { Cl } _ { 2 }$

Question 10 Multiple Choice (Single Answer)

Graphite melts at a high temperature of about:

$4236^oC$
$5326^oC$
$3527^oC$
$6326^oC$

Question 11 Multiple Choice (Single Answer)

The reaction between carbon and oxygen can be represented as
$C _{(s)}+O _{2(x)}\rightarrow CO _{2(g)}+heat$
In which of the following type(s), the above reaction can be classified?
I. Combustion reaction
II. Displacement reaction
III. Endothermic reaction
IV. Combination reaction

(I) and (III)
(I), (II) and (IV)
(I) and (IV)
(I) only

Question 12 Multiple Choice (Single Answer)

In the Earth's crust, Carbon is found in the form of_________.

carbonates
hydrogen carbonates
petroleum
All of the above

Question 13 Multiple Choice (Single Answer)

Which of the following is not an allotrope of carbon?

Graphite
Granite
Diamond
Fullerene

Question 14 Multiple Choice (Single Answer)

Who has synthesised the organic compound 'urea' for the first time?

Friedrich Wohler
Berzelelius
Kolbe
None of the above

Question 15 Multiple Choice (Single Answer)

An element which is an essential constituent of all organic compounds belongs to the_____group.

5th
8th
14th
12th

Question 16 Multiple Choice (Single Answer)

Carbon is a versatile element.

True
False

Question 17 Multiple Choice (Single Answer)

Using the given hints, identify the option with correct coal product and its use.
(1)$;;$Almost pure form of carbon.

Coke, manufacture of steel
Coal tar, manufacture of paints
Coke, manufacture of plastics
Coal tar, extraction of metals

Importance of carbon - class-VIII

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