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Why lime water turns milky when it gets exposed to carbon dioxide?

Which metal is used to galvanise iron to protect it from rusting ?

What happens when the magnesium ribbon is burnt in oxygn

What are the main points of Dalton atomic theory

Himanshu has two substances A and B. When red cabbage extract is added to substance A, it turns green. Whereas, when the extract is added to substance B, it turns light pink. In addition, the solution of A and B turns red litmus to blue. Which of the following statement(s) is/are correct?

Question 4 (iii)
What is meant by the following terms?

(iii) Sericulture

What is the defination of knitting and weaving ?

Water is known as the _________ because many substances dissolve in it.

The following data pertains to reaction between A and B :
$\begin{array}{cccc}S.NO.& \left[A\right]mol{L}^{-1}& mol{L}^{-1}& Rate\left(mol{L}^{-1}tim{e}^{-1}\right)\\ 1& 1.0\times {10}^{-2}& 2.0\times {10}^{-2}& 2.0\times {10}^4\\ 2& 2.0\times {10}^{-2}& 2.0\times {10}^{-2}& 4.0\times {10}^{-4}\\ 3& 2.0\times {10}^{-2}& 4.0\times {10}^{-2}& 8.0\times {10}^{-4}\end{array}$
Which of the following inference(s) can be drawn from the above data ?

1. Rate constant of the reaction is $1.0\times {10}^{-4}$

2. Rate law of the reaction is: rate $=k\left[A\right]\left[B\right]$

3. Rate of reaction increases four times on doubting the concentration of both the reactants.

Select the correct answer using the codes given below:

Which is the most essential element of life?

Particles in solids have ___________.

The electron affinities of N, O, S and Cl are :

When a little soil is mixed in water, some foamy things float on the surface of the water while others sink. What floats on the water?

Now, Deepika wants to clean water in her water plant, which of the following chemical should she use?

Which of the following describes weathering?

Which of the following acid is present in proteins? [1 MARK]

The pH values of different soil samples are given. Which of the soil should be treated with a base?

What is photosynthesis? Give the chemical equation for it. [2 MARKS]

Why is dilute sulphuric acid used in place of concentrated sulphuric acid to prepare copper sulphate?

Reason: Acid rain contains acids like nitric acid, which corrodes the upper layer of buildings and monuments.

what happens when

sodium hydroxide reacts with acetic acid

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

We can broadly classify water into saline water, frozen water and usable surface water. Which of the following correctly represents their availability on the Earth?

$CaO\left(s\right)+H_{2}O\left(l\right)\to Ca\left(OH{)}_2\right(aq)+heat$

What can be inferred from the above reaction?

(i) $CaO$ is solid.

(ii) $CaO$ can react easily with water.

(iii) $H_{2}O$ is liquid.

(iv) $H_{2}O$ is in vapour state.

(v) $Ca(OH{)}_2$ forms a solution with water

Heating zinc oxide is a physical change. How?

. What is the colour of phenolphthalein acidic and basic media?

Which type of reaction the following figure describe ?

When water is absorbed by paper towel, what kind of change are we observing?

If bases are bitter in taste are plants like bitter gourd and neem also bases?

State the reason why zinc is used in the galvanisation of iron and not copper.

A mixture of iron nails, oil, water, tea leaves and salt is provided to you. Give step-wise instructions to separate each component from the mixture? [5 MARKS]

Which inert gas is usually filled in balloons?

What are the various contaminants present in wastewater? Give examples. [2 MARKS]

Match the following.

Relate physical states used in chemical reactions to their symbols.

$\begin{array}{cc}\text{Physical State}& \text{Symbol}\\ \text{1. Gas}& \left(A\right)\left(dw\right)\\ \text{2. Solid}& \left(B\right)\left(g\right)\\ \text{3. Liquid}& \left(C\right)\left(aq\right)\\ \text{4. Dissolved in water (solution with water)}& \left(D\right)\left(l\right)\\ & \left(E\right)\left(s\right)\\ & \left(F\right)\left(v\right)\end{array}$

Explain colloid with examples? [3 MARKS]

Which of the following base do not contain metallic atoms?

The process by which a solid directly converts into its gaseous state is called

Anisha's father is having an issue of intense coughing. A doctor told him that his intense coughing is because of pollution. Which pollution you think is responsible for his illness?

Answer the following: [3 MARKS]

(a) When is it useful to apply sedimentation and decantation?
(b) Give two examples where these methods are used?
(c) Explain the process.

When copper turnings are added to silver nitrate solution, a blue coloured solution is formed after some time. It is because of copper

Which topsoil is best suited for growing plants?

Complete the following food chain:

Grass $\to$ Insects $\to$ Frog $\to$ ____$\to$ Eagle

What do you understand by water absorption rate?
It took 60 minutes for 360 mL of water to percolate through a soil sample. What is the rate of percolation for the soil sample? [5 MARKS]

Barium Chloride + Aluminium Sulphate $\to$Barium Sulphate +Aluminium Chloride

Which of the following options correctly represents the balanced chemical equation for the above reaction?

A neutron travelling with a velocity v and kinetic energy E has a perfectly elastic head-on collision with a nucleus of an atom of mass number A at rest. The fraction of total energy retained by the neutron is approximately