Explore topic-wise InterviewSolutions in .

The most abundant constituent of air is ___ .

(a)

Here is a crossword puzzle: Good luck!​

Across​

3. Liquid waste products​​





(b)

4. Solid waste extracted in sewage treatment





(c)

6. A word related to hygiene





(d)

8. Waste matter discharged from human body





(e)



Down​

1. Used water





(f)



Down​

2. A pipe carrying sewage





(g)



Down​

5. Micro-organisms which causes cholera





(h)



Down​

8. A chemical to disinfect water

Balance the following reaction:

3Fe + 4H₂O → Fe₃O₄ + __H₂

Glass is chemially ___ in nature.

What will be the atomicity of:

a) the molecule which is consumed during respiration and released during photosynthesis.

b) the red coloured element which is found on the tips of match sticks.

c) the pale blue gas which forms a layer that absorbs the sun's UV radiation.

Define crown of the tree. [1 MARK]

Study the diagrams representing mixtures,elements and compounds shown, and choose the correct statement from the following:

"दोनों घंटों बैठकर इन पाबंदियों से बच निकलने की तरकीबें सोचा करते थे।"

क्या तुम उन दोनों को इस तरकीब से भी अच्छी तरकीब सुझा सकती हो?

Which among the following is an example of reversible change?

Choose the correct statements in regard to salts from the following:

Statement 1: All salts are formed by the reaction of HCl and NaOH.

Statement 2: Salts are formed by the neutralization of acids and bases.

Statement 3: Salts are ionic compounds.

Statement 4: Salts are composed of cations and anions.

Statement 5: Salts are always white in colour.

Statement 6: NaCl is called as common salt.

Statement 7: pH of common salt is 7.

On what principle of the following methods of separation based give one example of a mixture for each of the methods mentioned in which they are used

A. Sublimation,and

B. Chromatography

Question 24

Oxygen is returned to the atmosphere mainly by:



(a) burning of fossil fuel

(b) respiration

(c) photosynthesis

(d) fungi

Question 6
Fill in the blanks with the appropriate solutions:

(a) People obtain groundwater through __ and __.
(b) Three forms of water are __, __ and __.
(c) The water bearing layer of the earth is __.
(d) The process of water seepage into the ground is called __.

Define and give one suitable example of each of the following:

(a) Precipitation

(b) Neutralisation

Column-I contains binary liquid mixture in ether and column-II contains method used for separation.



$\begin{array}{cccc}& \text{Column-I}& & \text{Column-II}\\ \text{P.}& \text{Aniline + N-methyl aniline}& \text{1.}& \text{i. Addition of}\left[Ag\right(N{H}_3{)}_2{]}^{+}\\ & & & \text{ii. Filteration}\\ & & & \text{iii. Treating precipitate with dil.}HCl\\ \text{Q.}& \text{Phthalimide + Benzyl amine}& \text{2.}& \text{i. Addition of}{C}_6{H}_{5}S{O}_{2}Cl+aq.NaOH\\ & & & \text{ii. Treating aq. layer with dil.}HCl\\ & & & \text{and distilled over}NaOH\\ \text{R.}& \text{Propan-1-ol + Propanone}& \text{3.}& \text{i. Addition of}NaOH\\ & & & \text{ii. Treating aqueous with}HCl\\ \text{S.}& \text{But-1-yne + But-2-yene}& \text{4.}& \text{i. Addition of saturated}NaHS{O}_3\\ & & & \text{ii. Filteration}\\ & & & \text{iii. Heating precipitate with dil.}HCl\end{array}$



Select the correct option considering column-I and column-II.

Which of the following are the types of solutions?

If blue litmus paper is dipped in vinegar solution, the color of litmus paper will change to:

Discuss the process of obtaining silk.

Previous question had a error it was :

What is the difference between a larve and cocoon ?

Question 44

Why does water need conservation even though large oceans surround the land masses?

(a) What happens when an acid reacts with a metal carbonate? Explain with the help of an example. Write chemical equation of the reaction involved.

(b) What happens when carbon dioxide gas is passed through lime water?