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Fractional distillation is used in separation of crude oil instead

Of simple distillation, why?

Which one of the following does not contribute to conservation of water?

Which metal is most commonly used for fertilizers?

What type of substance burns with a flame ? Can the answer be metals ??

________ is done to prevent almonds and cashews from becoming stale.

Be and Al compounds are largely covalent because of:

The process used to separate a mixture of two or more miscible liquids when the difference in their boiling points is less than $25{}^{\circ }C$ is ___.

When do we consider hydrogen as alkali metal?

How is the atomic configuration for elements zinc and above atomic number?

The different zones of a candle flame are marked with the letters A, B and C.


Which of the following is correct?

The suspended particles released by combustion of coal in air may lead to a health disease. Select the correct option.

A person was struck by heart attack then it is a:-

What is the term used for allotropes of carbon which are cylindrical nanostructure and extremely strong, thermally conductive, and very toxic?

What are Inexhaustible natural resources? Give 2 examples. [3 MARKS]

Are you aware of the term used for the phenomena where $O_2$ displaces $C{O}_2$ in lungs?

The substance has to reach this temperature before it catches fire.

The rate of a reaction is expressed in different ways as follows:
$\frac{1}{2}\left(\frac{d\left[C\right]}{dt}\right)=-\frac{1}{3}\left(\frac{d\left[D\right]}{dt}\right)=\frac{1}{4}\left(\frac{d\left[A\right]}{dt}\right)=-\left(\frac{d\left[B\right]}{dt}\right)$
The reaction is

In the following reaction, the value of y will be:

$3Fe+4H_{2}O\to F{e}_3{O}_4+y{H}_2$

Then, y = ___

The constituent of polluted air which contributes in producing acid rain is:

(a) nitrogen

(b) sulphur dioxide

(c) oxygen

(d) argon

Pick out the solids which change into vapours on heating and back to solids on cooling from the following options

What fire extinguisher contains?

A non-metal which exist as solid at room temperature is:

Write 'true' or 'false' against the following statements :

(a) Charcoal is a good adsorbent.

(b) Coke is obtained by destructive distillation of sugar.

(c) Activated charcoal is a good conductor of electricity.

(d) Wood charcoal is an important constituent of gun powder.

(e) Coal gas is used in the preparation of artificial fertilizers.

What do you observe when a gas jar which appears empty is inverted over a gas jar containing Bromine vapours ? Name the phenomenon.

From the knowledge of activity series, name a metal which shows the following properties

(i) It reacts readily with cold water

(ii) It displaces hydrogen from hot water

(iii) It displaces hydrogen from dilute HCI

(iv) It forms a base which is insoluble in water.

What are the properties of a colloid?

Which of the following is/are true about hydrogen:-

Which of the following metals, on reaction with acids like HCl form bubbles in the solution?

Which acid among the following is not used to produce hydrogen gas even in its dilute form on reacting with metals:-

How coal is formed ? What is the difference between coal and peat

U with atomic number 92 and mass number 238 is radioactive and it emits alpha and beta particles to form Pb with atomic number 82 and mass number 206. Calculate the number of alpha and beta particles emitted in this conversation.

An ore of U with atomic number 92 and mass number 238 is found to contain U and Pb in the weight ratio of 1:0.1. The half-life period of U is $4.5\times {10}^9$ years. Calculate the age of the ore.

How do industries cause water pollution?

Harry, John, Isha and Iqbal went for picnic. Isha was cutting some apples but in the middle of it,Harry took her to play volleyball. After coming back she saw a brown coating over the apple slices. This formation of brown coating is which kind of change?

The following equation represents double displacement reaction, what is the precipitate formed in this reaction?

$AgN{O}_3\left(aq\right)+NaI\left(aq\right)\to AgI\left(s\right)+NaN{O}_3\left(aq\right)$

How can we reduce global warming ?

(a) Define the calorific value of a fuel.

(b) "The calorific value of LPG is 55000 kJ/kg". What does it mean ?

Which of the following are the properties of plastic?

Select the fuel that causes less pollution, burns readily and can be used as a fuel in homes and automobiles.

Although rayon is obtained from a natural source, wood pulp, yet it is a man-made fibre. Why? [2 MARKS]