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.

Define the term scintillations?

Answer» SPARKLING or SHINING BRIGHTLY
2.

A compound is regarded as a pure substance while the mixture is not. Give reason?

Answer»

Because pure SUBSTANCES are BUILT by single element whereas MIXTURE is MADE of TWO or more elements

3.

Write name of element present in 1)sugar 2)lime

Answer»

Answer:

1) CARBON, hydrogen, oxygen

2) calcium oxide

Explanation:

HOPE this helps.

please MARK as Brainliest

4.

when the powder of a common metal is heated in an open china dish, its color turns black. however. when hydrogen is passed over the hot black substance so formed, it regains it original color. based on the above information answer the following questions. (A) what type of chemical reaction takes place in each of two given steps. (B) name the metal initially taken in the powder form. write balanced chemical equation for both reactions.

Answer»

A-in first CASE it is decomposition reaction and in the other case is combination reaction
B-the METAL is CuO
1- 2Cu+O2---->2CuO
2- CuO + H2---> Cu + H2O

5.

Plz answerWhat amount of bromine will be required to convert 2g of phenol into 2,4,6-tribromophenol??

Answer» 3 BR are REQUIRED...
6.

Why concentrated nitric acid turns yellow on exposure to sunlight

Answer»

Nitric acid takes YELLOWISH brown colour due to presence of dissolvednitrogen dioxide the colour of nitric acid changes due to release of oxides of NITROGEN especially nitrogen dioxide into the AIR upon exposure to light

7.

in the solid state .PCl5 as an ionic solid. the hybridisation of phosphorus in the cationic and anionic part are respectively?

Answer»

The CORRECT answer should be sp3 and sp3d2 because the PHOSPHOROUS in PCl5 EXISTS in both (PCl4)+ and (PCl6)- to INCREASE interionic bond attraction.....

8.

sulphur burns in oxygen to give sulphur dioxide .if 16g of sulphur burns in 'x'cc of oxygen . calculate the amount of potassium nitrate which must be heated to produce 'x' cc of oxygen.[S=32, K=39, N=14,O=16]

Answer»

Hii dear ___________❤️❤️❤️


good morning_______________✌️✌️✌️✌️


 
S      +   O2   → SO2
1mol    1mol        1mol

​Moles of S reacted = 16g/32G/MOL = 0.5 mol
0.5 mol of S needs 0.5 mol of Oxygen,

{To complicate the question x CC is mentioned in the question, which has no SIGNIFICANT use.}
So we know that Sulphur burns in 0.5 mol Oxygen.

The thermal decomposition of Potassium nitrate :
2KNO3  →  2KNO2 + O2
2mol                             1 mol

​[2 x 101g]                    32g O2


1 mol of O2 is produced by 2 mol of KNO3
​0.5 mol will thus be produced by 1 mol of KNO3

Thus 1mol of KNO3 is required to produce the given amount of Oxygen.
1mol of KNO3 = molar mass of KNO3 = 101g
Hence 101g of KNO3 is required.



9.

Why does distillation produce pure water but filtration does not?

Answer»

Because DISTILLATION MAKES water vapour and LEAVES the IMPURITIES behind and in filtration some impurities come with water

10.

Calculate the no of atoms of each kind in 5.3 g of sodium carbonate

Answer»

Here's your ANSWER. HOPE it HELPS

11.

A non metal which burns in air forming violet vapours

Answer»

That is IODINE it BURNS with VIOLET VAPOURS.

12.

Give reason sublimation is used to separate ammonium chloride

Answer»

AMMONIUM chloride is a sublime SUBSTANCE and HENCE can be separated through sublimation whereas other substances in the mixture will REMAIN there only(if not sublime substance)

HOPE IT HELPS YOU

13.

Why the marks of chalk on the blackboard are unable to be wiped out easily after a long time?

Answer»

It is so because little bit PARTICLES of chalk gets diffused into the BLACKBOARD and HENCE are difficult to remove.
You can EVEN try it.

HOPE IT HELPS U☺☺☺

14.

A mixture of co and co2 has vapour density 20 at stp. 100 g of this mixture contains:

Answer»

Hey dear,

● Answer -
0.625 moles of CO
1.875 moles of CO2

EXPLANATION -
# Given-
Vapor density = 20

# Solution-
Molar WEIGHT of mixture = 2 × vapor density = 2 × 20 = 40

Let
x = mole fraction of CO
1-x = mole fraction of CO2

Therefore,
28(x) + 44(1-x) = 40
28x + 44 - 44x = 40
16x = 4
x = 0.25

No of moles of CO will be -
n1 = 0.25 × 100 / 40
n1 = 0.625 moles

No of moles of CO2 will be -
n2 = (1-0.25) × 100 / 40
n2 = 1.875 moles

Therefore, 100 g of mixture contains 0.625 moles of CO and 1.875 moles of CO2.

Hope this helps...

15.

What is inductive effect ?

Answer»

hey...

INDUCTIVE EFFECT is a electronic effect DUE to the polarizing of an BOND




16.

What would happen when a pinch of washing soda is added to dilute sulphuric acid?

Answer»

hey...

Washing soda is SODIUM carbonate.​Sodium carbonate reacts with sulphuric acid to FORM sodium sulphate, water and carbon DIOXIDE.


:)


17.

How would we decide whether a change is physical or chemical mention two characteristic of each kind of change

Answer»

hey..


if that substance is reversable or the substance in the BEGGINING is BROUGHT back again by COOLING then it is PHYSICAL change or else if u are not GETTING or it is irreversable then it is a chemical change

:)


18.

If there's no oxygen in space how does the sun 'burn' ?

Answer»

hey..

the Sun can BURN hydrogen to helium without the need for oxygen. It should be in the presence of CARBON, nitrogen and oxygen, stars heavier than the Sun may burn hydrogen to helium by USING the C, N and O as catalysts. Even in these stars, however, an ABSENCE of oxygen does not prevent nuclear burning.

19.

what happens when dilute hydrogen acid is added to sodium carbonate write a balanced chemical equation of the reaction involved

Answer»

HEY..

Na2CO3 + HCl ----> NaHCO3 +NACL

As more HCl is added the sodium BICARBONATE reacts with it to PRODUCE CO2, NaCl and H2O;-

NaHCO3 + HCl ----> NaCl + CO2 + H2O

:)

20.

in addition to formation of a new substance what all changes can be observed during a chemical change give one example of each type of change

Answer»

hey..


we can OBSERVE

-change in colour

-change in state

-evolution of a gas

-change in TEMPERATURE

21.

State reasons for the following : (a) Iron articles get coated with a reddish brown powder when left for sometime in open. (b) Burning of coal is an exothermic reaction.(c) The chemical equations should be balanced.

Answer»

hey...

The reddish brown layer on iron is rust. It is OBTAINED due to RUSTING of that metal.When an iron metal is attacked by SUBSTANCES AROUND it such as moisture,acids etc.. it is said to be corroded or rusted. That is why we find iron articles coated with that layer.

:)


22.

what happens when an acid reacts with a metal hydrogen carbonate write equation of the reaction which takes place

Answer»

METAL carbonate/metal HYDROGEN carbonate+acid GIVES salt+co2+water

23.

A 10 gm of sample mixture of calcium chloride and sodium chloride is treated with na2co3 to

Answer»

CaCO3 +heat--->CaO +Co2
X gms               1.68gms
100                   56
[molecular mass of CaCO3=100u
molecular mass of CaO=56u]
cross multiply through the equation and solve for x grams of caco3
x=1.62x100/56
=2.89g
Cacl2 +Na2Co3 --->Caco3 +2 Nacl
x                             2.89g
111                         100
Again cross multiply through the equation and solve for x grams of Cacl2
x=2.89x 111/100
=3.2g
%CaCl2 in original MIXTURE 3.2grams 
Cacl2 over 10gms mixture is 32%

24.

Calculate the molar mass of HNO3 (nitric acid) and H2SO4 (sulphuric acid)

Answer» MOLAR MASS of nitric ACID = 63
molar mass of H2SO4
= 98
25.

What will we observe on surface of zinc granules when sulphuric acid is added on zinc granules

Answer»

Hey Troll1478,


Zinc is more REACTIVE than hydrogen and it displaces hydrogen from DILUTE acids. Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen GAS is evolved. This is a single displacement REACTION of a non-metal by a metal.


hope dis helps u!



With REGARDS,

26.

Caco3=cao+co2 whether it is endothermic or exothermic

Answer» ENDOTHERMIC because CACO3 are BREAKING for CAO +CO2
27.

2kclo3=2kcl+3o2 whether it is endothermic or exothermic

Answer»

It's ENDOTHERMIC REACTION.

28.

When is a solution said to be saturated? how can you change a saturated solution into an unsaturated solution without adding any more solvent to it? explain in brief?

Answer»

When a solution doesn't have solute dissolved, is said to be saturated.

is the solubility of the solute is in the SOLVENT and DIRECTLY proportional to TEMPERATURE then increasing the temperature of the system will make it unsaturated

29.

Write the Zeisel’s Method

Answer»

Hey mate here is your answer☺️☺️


A METHOD for the determination of methoxyl and ethoxyl groups in organic compounds, in which the substance is heated with hydriodic acid; the iodoalkane THUS formed is PASSED into an ethanolic solution of SILVER I NITRATE, and the resulting silver I iodide weighed.

Hope it helps you:D

30.

What is chemical name for CH4

Answer» CHEMICAL NAME is METHANE.

THANK you
31.

Give the two examples from everyday life situations, where redox reactions are taking place.

Answer» SPOILING of oilly FOOD MATERIALS
32.

A substance or matter's mass is 1kg at room temperature and 2kg at its melting point and 3kg at its boiling point?

Answer»

Specific Heat and Latent Heat

Specific heat: = energy required to change a unit mass of a material by 1°C. Units: energy per unit mass per degree.

Latent heat = energy required to change the state (gas, liquid, solid) of a unit mass of material. Units: energy per unit mass.

Both specific heat and latent heat are properties of a given material. In other words, every time the material is heated/cooled, no matter how quickly or by what heating process, the same amount of heat is transferred to reach the same state.

Change in energy of a substance:

To raise/lower its temperature:
DE = CpM DT

To change its state:
DE = LM

where 
DE = change in energy
DT = temperature change
M = mass
Cp = specific heat
L = latent heat

Energy must be added

to increase the temperature

to melt it 

to evaporate it

Energy is released when a substance

cools

condenses

freezes

Energy units:

Ergs (1 ERG = 1 g cm2 s-2)

JOULES (1 J = 1 kg m2 s-2 = 107 ergs)

Calories (1 cal = 4.184 J)

Total energy to raise temperature of 1.0 kg of water from 10°C to 110°C

Cpwater = 4.2 x 103 J kg-1 °C-1
Cpsteam = 2.0 x 103 J kg-1 °C-1
Lvaporization = 2.3 x 106 J kg-1
M = 1 kg

DE = energy to heat water to boiling point + 
energy to change state + 
energy to raise temperature of steam
= Cpwater MDT + LvaporizationM + CpsteamMDT
= (4.2 x 103 J kg-1 °C-1)(1 kg)(90°C) + (2.3 x 106 J kg-1)(1 kg) + (2.0 x 103 J kg-1 °C-1)(1 kg)(10°C)

= 2.7 x 106 J

Total energy released at midocean ridges by formation of new oceanic crust


Cpbasalt = 1.4 x 103 J kg-1 °C-1
Cpmagma = 1.0 x 103 J kg-1 °C-1
Lmelting = 4.0 x 105 J kg-1
Temperature of magma when erupted = 1300°C
MELTING point 1200°C
Temperature of sea water = 0°C
Length of ridge = 60,000 km = 6 x 107 m
Crustal THICKNESS = 5 km = 5 x 103 m
Average SPREADING rate 2 cm yr-1 = 2 x 10-2 m yr-1
Density of basalt 3 x 103 kg m-3

1. Mass of magma solidified (per year) = volume x density
= ridge length x crustal thickness * spreading rate* density
= (6 x 107 m)( 5 x 103 m)( 2 x 10-2 m yr-1)( 3 x 103 kg m-3)
=2 x 1013 kg yr-1

2. DE = energy to solidify and cool crust (per year)
= energy to cool magma to melting point +
energy to solidify magma + 
energy to cool basalt to ocean water temperature

DE = Cpmagma MDT +
LmeltingM +
CpbasaltMDT
= (1.0 x 103 J kg-1 °C-1)(2 x 1013 kg)(100°C) +
(4.0 x 105 J kg-1)(2 x 1013 kg) +
(1.4 x 103 J kg-1 °C-1)(2 x 1013 kg)(1200°C)
= 2 x 1018 J + 8 x 1018 J + 3 x 1019 J

= (4 x 1019 J)(107ergs/ J)= 4 x 1026 ergs

33.

Why do stars twinkle,what's the phenomenon, what happens?

Answer»

In the stars there is REACTION of hydrogen and helium which produces a lot of LIGHT ENERGY so it twinklea

34.

Why should magnesium ribbon be cleaned before burning in air?

Answer»

Because when it is kept OUTSIDE it REACTS with OXYGEN and forms an layer of oxide which prevents BURNING.

35.

on heating to 216 gram of mercuric oxide we get X gram of Mercury and 16 gram of oxygen the value of x is

Answer» 200GM 216-16=200 I HOPE it will HELP you
36.

Describe thermodynamic scale changes when a gas is adsorbed on a solid

Answer»

That is of 2 types of adsorption in this case :-

1)physisorption: gas is BOUNDED by van der wal's force.

2) CHEMISORPTION: gas is bounded chemically

Now if it's spontaneous Gibbs energy will be negative if not positive.

And remember by adsorption the SYSTEM gets ordered so you can expect a negative impact on entropy.

Now, the Thermodynamic change from more entropy to LESS entropy in terms of magnitude should release energy from the system, so, it can be exothermic, though it depends on the specific EXAMPLE you are thinking.
I think it's helpful for u

37.

a certain mass of a gas occupies to litres at 27 degree Celsius and hundred Pascal find the temperature when volume and pressure become half of the initial values

Answer» 75 KELVIN by APPLYING pv=nrt
38.

When is a chemical reaction considered a double displacement reaction,explain giving ex ,a state a difference between displacement?

Answer» DOUBLE DISPLACEMENT reaction is when two high
reactive METAL displace the two less reactive metal from their aqueous solution exNA2SO4+K2CO3-K2SO4+NA2CO3 displacement reaction is when the more reactive metal displace the LOW reactive metal.
39.

Formula of calcium chloride

Answer» CACL2 is the FORMULA of CALCIUM CHLORIDE
40.

Which solution is used to dissolve gold

Answer»

Aqua Regia is the SOLUTION is USED to DISSOLVE GOLD

41.

Which metal does not produce hydrogen when added to dilute hydrochloric acid

Answer»

The products of acid/metal reactions are a salt and HYDROGEN GAS. Some METALS are so unreactive that they do not react with DILUTE acids at all, e.g. COPPER, silver and gold.

42.

Pb(no3) on heating what is the reaction

Answer» HOPE this HELPS you.
43.

Name the two kinds of plastic and their uses

Answer»

PVC - USED for MAKING SANITARY PIPES


44.

Food cans are coated with tin and not with zinc because

Answer»

Because zinc has higher MELTING POINT than TIN, zinc is more REACTIVE than tin which may react with food items and make it unfit for health ....and also zinc is costlier than tin...

........hope this may help you......

45.

The melting points of Cu,Ag and Au follow the order.

Answer»

Explanation:

Melting POINT is defined as the temperature at which SOLID starts to convert into LIQUID state.

It is known that copper, silver and gold all are transition METALS. Their melting points are listed as follows.

Copper - 1984^{o}F or 1085^{o}C

Gold - 1948^{o}F or 1064^{o}C

Silver - 1763^{o}F or 961.8^{o}C

Hence, we can conclude that melting points of given elements from increasing to decreasing order are as follows.

                                CU > Au > Ag

46.

What is effervescence?

Answer»
1.

bubbles in a LIQUID; FIZZ.

"the effervescence of sparkling WINE"

2.

vivacity and enthusiasm.

"he was FILLED with such effervescence

47.

Which has the maximum standard oxidation potential.(1) Zn (2) Cu (3)Ag (4)Mg

Answer»

(2) CU has the MAXIMUM STANDARD oxidation POTENTIAL

48.

What is organic and inorganic compounds?

Answer»

Organic COMPOUND


In chemistry, an organic compound is generally any chemical compound that contains carbon. Due to carbon's ability to CATENATE, millions of organic compounds are known as Organic compound.


Inorganic compounds


An inorganic compound is typically a chemical compound that lacks C-H bonds, that is, a compound that is not an organic compound, but the distinction is not DEFINED or EVEN of particular interest.

49.

Smoke and fog both are aerosols. In what way are they different?

Answer»

Smoke and fog both are aerosols. In what way are they different? Smoke –Smoke is mixture of gases and can GOES to HIGHER altitudes because of having more temperature. ... Fog is settled NEAR the earth SURFACE because of less temperature

50.

Equivalent weight of metal oxide is 17 then equivalent weight of metal chloride is

Answer» MARK BRAINLIEST PLEASE.