Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Why do all substances do not produce flame on burning

Answer»

As all the SUBSTANCE do not EVOLVE HYDROGEN GAS on BURNING

2.

Explain the rule according to which electrons are filled in the various energy level

Answer»

Electrons are filled according to aufbau principle into VARIOUS energy LEVELS..it's also CALLED (n+L) RULE..where n=principle quantum number and l is azimuthal quantum number

3.

How many moles and how many gram of Nacl are present in 250ml of 0.50M in a solution

Answer»

Bonjour!

No. of moles = ?
Gram of NACL = ?
Molecular weight of NaCl = 58.5 g
Volume of solution = 250 ML
Molarity = 0.50 M or M/2


molarity =  \frac{<klux>MOLE</klux> \: of \: solute(nacl)}{volume \: of \: solution \: in \: liters}

So,
=  >  \frac{1}{2}  =  \frac{mole \: of \: nacl}{ \frac{250}{1000} }  \\  \\  =  >  \frac{1}{2}  =  \frac{mole \: of \: nacl}{ \frac{1}{4} }  \\  \\  =  > mole \: of \: nacl =  \frac{1}{2 \times 4}  =  \frac{1}{8} mol

So, Mole of NaCl = 1/8 mol

As we know;
no. \: of \: mole \:  =  \frac{given \: weight}{molecular \: weight}

So,
=  >  \frac{1}{8}  =  \frac{given \: weight}{58.5}  \\  \\  =  > given \: weight =  \frac{58.5}{8}  = 7.3125gm
Therefore there are 1/8 mole and 7.3125 gm of NaCl present in 250 ml of 0.50M solution.

Hope this HELPS...:)

4.

Why blue crystals of copper sulphate on heating in dry test tube becomes colourless?

Answer» HEY mate!!

➡️The blue COLOURED copper sulphate crystals turns white due to the loss of water MOLECULES. The FORMULA OFCOPPER sulphate is CuSO4.5H2O. Whencopper sulphate is heated, it looses water molecules and hence it loosesblue colour.
5.

Examples of reversible changes

Answer» THROWING a PEICE of PAPER on the ground.
Crushing a paper
6.

Name at least ten metals

Answer»

Tin
copper
alluminium
gold
SILVER
bronze
lead
iron
zinc
titanium
cobalt

7.

Does the value of acceleration due to gravity vary from planet to planet

Answer» YES it VARIES from PLANET to planet
8.

The wave nature of electron was experimentally confirmed by

Answer» DAVIDSON CONFIRMED it
9.

Explain why filter paper cannot be used to separate colloids.

Answer» PARTICLES of COLLOIDS RANGE from 1 to 100nm. It is very small that it can't be seen with naked eyes.even it is SMALLER than the hole of the filter PAPER,thus it can't be separated by filter paper but can be separated by ultra filtration
10.

I want experiment of NaSo4, BaCl2 in step by step .

Answer»

This MAY HELP U.........

11.

What is an Metalloid? Write four metalloids.

Answer»

Hey mate!!!

➡️Metalloid that has the VISUAL appearance of a metal, but is a poor CONDUCTOR of ELECTRICITY; metalloids are generally semiconductors. The ELEMENTS classified as metalloids are boron,silicon, germanium, arsenic, antimony,tellurium, and polonium.

12.

Why does ice cream appears colder than water at the same temprature?

Answer» DUE to CONDUCTION.......
13.

Comment upon the following:Rigidity,compressibility,fluidity,shape,kinetic energy,and density of various states of matter.

Answer»

Rigidity-it is a property by which a SUBSTANCE RETAIN its shape when force is applied to it
compressibility-the property by vertue of which the volume of substance can be decreased
fluidity-it is the property by vertue of it the molicules of one substance can flow from one point to another
shape-it is the definate geometrical arrangement of a substance
kinetic energy-the energy possesed by a PARTICLE due to its motion is called...
density-the mass PER UNIT of volume of a substance is called density
density=mass/volume

14.

Effect of inductive effect on acidity of carboxylic acid

Answer»

ANSWER:

EXPLANATION:

DECREASES the ACIDITY due to INDUCTIVE effect

15.

Colloid solution appears to be homogeneous but actually it is hetrogeneous comment?

Answer»

In SOOTH, it APPEARS to be but it isn't when seen with the HELP of a microscope..... Colloidal particles can't be seen with a naked eye

16.

Why should we wear cotton cloth in summer?

Answer»

We should wear COTTON clothes in SUMMER because ,due to heat during summer DAYS our body becomes sweaty and this SWEAT is easily EVAPORATE from the cotton clothes so we should wear cotton clothes during summer days.

17.

Name the different types of hydrogen

Answer» PROTIUM
deuterium
tritium
18.

Give reason why silver exhibits a valency of +1 and +2 icsc

Answer»

ANSWER:

Explanation:

Silver has a VARIABLE VALENCY, hence shows both OXIDATION state

19.

give reasons for the following observations The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go

Answer»

Hot FOODS smell goes farther BCOZ the particles of smell will diffuse air in form of SMOKE so by DIFFUSION of smell particles it happens

20.

Doctors advice to put strips of wet cloth on the forehead of a persons having high temperature

Answer»

To REDUCE HIGH TEMPERATURE in our BODY

21.

Name the oxidising agent and reducing agent in the following reaction- zinc oxide reacts with carbon, on heating to form Zinc metal and carbon monoxide

Answer» OXIDISING AGENT - CARBON
REDUCING agent - ZINC
22.

What is the pH of baking soda

Answer» HEY MATE!!

◀️ph value of baking SODA is 9

hope it HELPS u
23.

Why we can't take any burning material within the premises of ammunition depots

Answer»

ANSWER:

Explanation:

depots MIGHT CATCH FIRE and lead to an ACCIDENT

24.

how will you explain the following observations? Ice at 273 K is more effective in cooling than water at 273 K.

Answer»

Ice at 273 k is more EFFECTIVE in cooling than WATER at 273 k because water have some HEAT dissolved in it in the form of latent heat of FUSION which is not present in ice at same temperature

25.

Fuse (glass) 5 a 250 v dia : 5*20 mm h.r.c filled w/silica

Answer»

It's EASY to tell if a glass fuse is blown; it will show scorch MARKS, and the filament will be melted. To check a ceramic fuse, USE an ohmmeter or continuity TESTER. With an ohmmeter or multimeter, you should see a reading close to zero ohms if the fuse is INTACT, or infinite if it's blown.

26.

Why do atomic masses of most of the elements in atomic mass unit involve fraction?

Answer»

The ATOMIC masses of most elements are fractional because they exist as a MIXTURE of isotopes of DIFFERENT masses.Most elements occur as a mixture of isotopes of differentmasses. The fractional atomic masses ARISE because of this mixture. ... mass = TOTAL mass of all atoms/number of atoms.

27.

In a solution of copper nitrate, copper plate was dipped, after some time silver from the solution was deposited on the copper plate. which metal is more reactive copper and silver

Answer»

Answer:

Explanation:

The copper PLATE was immersed in silver NITRATE solution. After some TIME, a black layer was observed on the surface of the copper plate. GIVE reasons for this and WRITE the chemical equations of the reaction involved.

28.

How to decide whether a given solution is acidic basic or neutral?

Answer»

By OBSERVING the COLOUR changes in a PH paper we determin whether a solution is acidic basic or neutral and its STRENGTH

29.

Give reason magnesium ribbon is to be cleaned before burning in air

Answer»

The magnesium ribbon is QUITE reactive ELEMENT .it Pp reacts with atmospheric oxygen to produce a layer of magnesium oxide which PREVENT it from Burning. HENCE, we have to clean it with the Sandpaper to remove it.

30.

7. State two characteristic features of of each: a) Solidb) liquid c) gas

Answer»

1.solid
is rigid.
more HEAVY than LIQUID.
have FIXED VOLUME and SHAPE.
2.liquid
is fluid.
have fixed volume.
3.gas
is fluid.
neither have fixed volume nor fixed shape.

31.

Explain how the rate of evaporation of a liquid is affected with decrease in exposed surface area

Answer»

As surface area is DIRECTLY PROPOTIONAL to evaporatio SINCE it get AFFECTED by it

32.

Is evaporation of petrol a chemical change or a physical change?

Answer»

Evaporation of PETROL is a physical change because no NEW chemicalsubstance is FORMED

33.

If a gas jar containing air is placed in upside down position over a gas jar full of red-brown bromine vapour by a student, then explain what his/her observation will be and what is the property of matter which is shown by this activity

Answer»

Observation : the RED brown vapour will spread in both the JARS
PROPERTY of MATTER : SPACES in particles and diffusion

34.

How many molecules of oxygen are present in 1ltr air containg 80 percent volume of o2 at stp?

Answer»

Percentage of OXYGEN in air is 80%

percentage = VOLUME of the oxygen/volume of air ×100

80 = volume of oxygen/1L × 100

80L × 1/100 = volume of oxygen

0.8L = volume of oxygen

[or you can directly do it like in 1L air percentage of oxygen is 80 MEANS 0.8L oxygen and 0.2L other substance]
_____________________________________________________

We KNOW that one mole of any substance CONTAINS 22.4L volume in STP (standard temperature and pressure) so,

volume = number of moles ×22.4

volume/22.4 = number of moles

0.8/22.4 = number of moles

0.036 = number of moles
______________________________________________

we know that one mole of any substance contains 6.022×10^23 molecules.

molecules = number of moles × 6.022×10^23

molecules = 0.036 × 6.022 × 10^23

molecules = 0.216 × 10^23

molecules = 2.16 × 10^22 " O2 molecules ”
_______________________________________________

use can directly find it use this formula
molecules = volume of substance/22.4 × 6.022×10^23

35.

Calculate the number of moles and number of atoms present in 11.2 litre of oxygen o2 at ntp

Answer»

Hello there
I'm attaching a picture of the ANSWER
Hope it helps...and don't forget to MARK the answer brainliest if you really find it useful.
doubts are ALWAYS WELCOME...
Thanks

36.

Llama and alpaca are used for obtaining

Answer» OBTAIN the ZEROES of POLYNOMIAL
37.

Why electrovalent compound is soluble in water but insoluble in organic solvent

Answer»

Water is a POLAR covalent COMPOUND. It decreases the electrostatic forces of attraction, RESULTING in FREE ions in AQUEOUS solution. Hence, ionic compounds dissolve in water. Kerosene is a non-polar organic solvent and dissolves non-polar covalent compounds.
pls mark brainliest 

38.

Which of the following has both fixed shape and fixed volume ? a) 1kg milk b) 1kg of copper c)1kg nitrogen d) 1kg of water

Answer»

Hii
.
.
.
.
The Answer is (B) 1kg of COPPER.
.
.
It May Be HELP You

PLZ.. Mark As BRAINLIEST.....

39.

A sponge can be compressed. is it solid or not

Answer»

Yes it is solid it can be COMPRESSED becoze it have pores INSIDE it which ALLOW air to PASS.

40.

What is fractional atomic mass?

Answer»

The atomic MASSES of most elements are FRACTIONAL because they exist as a MIXTURE of isotopes of different masses. Most elements OCCUR as a mixture of isotopes of different masses. The fractional atomic masses arise because of this mixture. Avg. mass = total mass of all atoms/number of atoms.

41.

the smell of hot sizzling food reaches you several metres away but to get the smell from cold food you have to go close

Answer»

This is because of the TEMPERATURE in kinetic ENERGY of the PARTICLES ALSO increases and the diffuse into the AIR and reaches us to very quickly .

42.

classify each of the following as homogeneous or heterogeneous mixture (1) soda water (2) wood (3) air (4 ) soil (5) vinegar (6) filter tea

Answer»

Soda water , AIR ,vinegar and filtered TEA are homogeneous while sooo and wood are HETEROGENEOUS MIXTURE.....

43.

Conversion of acetaldehyde into acetone

Answer»

Conversion of acetaldehyde into acetone INVOLVES two steps as follows. Step-1:—Conversion of acetaldehyde to isopropyl alcohol. Acetaldehyde is treated with methyl magnessium bromide in PRESENCE of dry ether to form Mg complex which on acid hydrolysis,isopropyl alcohol is OBTAINED.

44.

Hard water is softened before being used in boilers

Answer»

Hey mate here is ur ANSWER..............

because hard WATER contains DISSOLVED salts of magnesium and calcium.When such water is heated in boilers it decomposes and 
a hard layer of calcium and magnesium carbonate is DEPOSITED at the bottom of boilers. In due course this layer renders the 
boilers useless. so it is softened before boiling .A water softener removes hard water minerals, like calcium and magnesium.


hope it may HELP u dear.......

45.

The number of unpaired electrons present in the first excited state of chlorine atom is

Answer» UNPAIRED E are 3 in FIRST exicted STATE
46.

Mention schrodinger wave equation

Answer»

After much debate, the wavefunction is now accepted to be a probability distribution. The SCHRODINGER equationis used to find the allowed energy LEVELS of quantum mechanical systems (such as atoms, or transistors). The associated wavefunction gives the probability of finding the PARTICLE at a CERTAIN position.

47.

A Solution contains 15 g of sodium chloride in 285 g of water. Calculate concentration of solution

Answer»

CONCENTRATION of SOLUTION
= AMOUNT of SOLUTE/ amount of SOLVENT
=15/285
=1/19
=.0526

48.

What happens to molecules of Solid,Liquid and gas when heated?

Answer»

SOLID changes into liquid by heating. Liquid changes into gas by heating. if a molecule of a solid liquid gas is heated the solid and liquid the solid molecule will CHANGE into liquid and liquid into gas. But the TEMPERATURE of gas is INCREASES

49.

what is Aqua regia? name two special metals which are insoluble in common reagents but dissolve in Aqua regia

Answer»

Aqua regua is a ACID
The metals which can be DISSOLVED in it are :
1 gold
2 platinum
3 palladium

50.

Tertiary amine do not react with benzene sulphonyl chloride

Answer»

ANSWER:

Explanation:

Yes,it is TRUE as there is no acidic hydrogen in TERTIARY amine.Only primary and secondary amine can react as they have 2 and 1 acidic hydrogen respectively which is required for REACTION with benzene SULPHONYL chloride.Hope you understood.