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.

Calcium phosphide is :

Answer»

`Ca_3P`
`Ca_2P_2`
`Ca_2P_3`
`CaP_2`

ANSWER :B
Discussion
2.

Calcium phosphide gets hydrolysedand give

Answer»

`Ca_(3)(PO_(4))_(2)`
`PH_(3)`
`H_(3)PO_(4)`
`(HPO_(3))_(N)`

ANSWER :D
Discussion
3.

Calcium oxalate is soluble in dilute HCl. Explain.

Answer»

Solution :
When dilute HCl is ADDED to calcium oxalate the oxalate ions will combine with `H^(o+)` ions of HCl to give feebly ionised soluble oxalic ACID.
`HClhArrH^(o+)+CL^(ɵ)`
Discussion
4.

Calcium occurs in nature as:

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Limestone
Marble
Dolomite
All

Answer :D
Discussion
5.

Calcium lactate is a salt of a weak organic acid and is represented as Ca(Lac)_2. A saturated solution of Ca(Lac)_2 contains 0.13 mol of this salt in 0.5 litre solution. The pOH of this solution is 5.6. Assuming complete dissociation of the salt, calculate K_a for latic acid.

Answer»

Solution :`Ca(LAC)_2(s) to Ca(Lac)_2(aq) TOCA^(2+)(aq) + 2LAC^(-) (aq) `
`Lac^(-) (aq)+ H_2O hArrLaCH(aq) + OH^(-) (aq)`
Since it is salt of strong base and weak acid, its PH is CALCULATED as
pH=14-pOH=14-5.6=8.4
`8.4= 1/2[14+pK_a + log 0.52]` (`therefore`c = 2 × 0.13/0.5)
`pK_a`=(2 × 8.4) – 14 – log 0.52 = 3.08
`thereforeK_a=8.31xx10^(-4)`
Discussion
6.

Calcium is obtained by-

Answer»

Roasting of LIME stone
Electrolysis of calcium chloride in `H_(2)O`
REDUCTION of calcium chloride with Carbon
Electrolysis of MOLTEN ANHYDROUS calcium chloride

Solution :`CaCI_(2)` (molten) `overset("Electrolysis")rarr underset("Cathode Ca")underset(darr)(Ca^(2+)+CI^(-))`
Discussion
7.

Calcium is extracted by the electrolysis of:

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FUSED mixture of `CaCl_2 and CaF_2`
`CaCl_2` solution
Fused mixture of `CaCl_2` and NAF
`CA(PO_4)_2` solution

Answer :A
Discussion
8.

Calcium is obtained by :

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Electrolysis of solution of `CaCl_(2)` in water
Electrolysis of molten `CaCl_(2)`
Heating CALCIUM OXIDE carbon
By nitrating calcium carbide.

Answer :B
Discussion
9.

Calcium imide on hydrolysis will give gas (B) which on oxidation by beaching powder gives gas (C) gas (C) on reaction with magnesium give compound (D). (D) on hydrolysis gives gas (B). (B), (C) and (D) are

Answer»

`NH_(3), N_(2),Mg_(3)N_(2)`
`N_(2), NH_(3), MgNH`
`N_(2), N_(2)O_(5), Mg(NO_(3))_(2)`
`NH_(3), NO_(2),Mg(NO_(2))_(2)`

Answer :A
Discussion
10.

Calcium formate on .................. gives methanal and CaCO_3

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SOLUTION :DRY DISTILLATION
Discussion
11.

Calcium has face-centred cubic lattice and radius of calcium atom is 195.6 picometre. Determine the number of Ca atoms present on surfaces of a mm3 block of calcium metal assuming that atoms in the closest packing calcium metal assuming that atoms are in the closest packing.

Answer»

Solution : In FCC, the relation is

`4r=sqrt(2a) impliesa=2sqrt(2r)=553.24xx10^(-9) mm`
`implies` Area of a face pf unit cell
`=a^(3)=3.06xx10^(-13)mm^(2)`
`implies` SURFACE area of metal BLOCK =6 `mm^(2)`
`implies` Total number of FACES of unit CELLS present on surface
`=(6)/(3.06xx10^(-13))=1.96xx10^(13)`
Each face contributes two two Ca atoms on surface as
`implies` Total number of Ca atoms present on surface
`=2xx1.96xx10^(13)=3.92xx10^(13)`
Discussion
12.

Calcium formate, on dry heating, produces

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acetone
ACETIC acid
acetaldehyde
formaldehyde

Solution :We know that
`(HCOO)_(2)CA overset(DELTA) toHCHO + CaCO_(3)`.
Thus in this REACTION, formaldehyde (HCHO) is PRODUCED.
Discussion
13.

Calcium does not combine directly with

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Oxygen
Nitrogen
Hydrogen
Carbon

Solution :REFER to COMPREHENSIVE REVIEW.
Discussion
14.

Calcium cynamide is

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`CaCHNH_(2)`
`CaCN_(2)`
`CaC_(2)N_(2)`
`Ca(CN)_(2)`

Answer :B
Discussion
15.

Calcium cyanamide reacts with steam to form ammonia and………

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`CA(OH)_2`
CAO
`Ca(HCO_3)_2`
`CaCO_3`

ANSWER :D
Discussion
16.

Calcium cyanamide on treatment with steam produce

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`CaCO_(3)+NH_(3)`
`CaHCO_(3)+NH_(3)`
`CaO+NH_(3)`
`Ca(OH)_(2)+NH_(3)`

Solution :Calcium CYANAMIDE on treatment with STEAM produces `CaCO_(3)+NH_(3)`.
Discussion
17.

Calcium cyanamide on treatment with steam under pressure gives ammonia and

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Calcium CARBONATE
Calcium HYDROXIDE
Calcium OXIDE
Calcium BICARBONATE

Answer :A
Discussion
18.

Calcium cyanamide on treatment with steam produes

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`NH_3+CaO`
`NH_3 + CaHCO_3`
`NH_3+CaCO_3`
`NH_3+Ca(OH)_2`

Solution :`underset("Calcium CYANAMIDE")(CaCN_(2))+underset("STEAM")(3H_2O)rarrCaCO_3+2NH_3`
Discussion
19.

Calcium crystallizes in Face-centred cubic lattice with edge length equals to 556 pm. calculate the density if : (i) There is 0.1% Schottky defect (ii) There is 0.1 % Frenkel defect

Answer»


ANSWER :`(i) 1.543 G cm^3(II) 1.545 g//cm^3]`
Discussion
20.

Calcium cyanamide on hydrolysis with steam gives

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`Cl_2`
`NH_3`
`O_2`
`CO_2`

ANSWER :B
Discussion
21.

Calcium carbonate reacts with aqueous HCl to give CaCl_(2) and CO_(2) according to the reaction : CaCO_(3)(s)+2HCl(aq) rarr CaCl_(2)(aq)+CO_(2)(g)+H_(2)O(l) What mass of CaCl_(2) will be formed when 250 mL of 0.76 M HCl react with 1000 g of CaCO_(3)? Name the limiting reagent. Calculate the number of moles of CaCl_(2) formed in the reaction.

Answer»

Solution :`"1000 g of CaCO"_(3)="1000/100 MOL = 10 mol "("Molecular mass of "CaCO_(3)="100 g mol"^(-1))`
`"250 mL of 0.76 M HCl "=250xx0.76" millimole = 190 millimole = 0.19 mol"`
According to the given equation, 1 mol of `CaCO_(3)` REACTS with 2 mol of HCl
`therefore" 10 mol of "CaCO_(3)" will react with 20 mol of HCl"`
But we have only 0.19 mol HCl. Hence, HCl will be limiting reagent.
2 mol of HCl produce `CaCl_(2)` = 1 mol
`therefore " 0.19 mol of HCl will produce "CaCl_(2)=(1)/(2)xx0.19" mol"=" 0.095 mol"= 0.095xx111g=10.54h`
`""("Molar mass of "CaCl_(2)=40+71="111 g mol"^(-1))`
Discussion
22.

Calcium carbonate used in the extraction ofiron acts as:

Answer»

OXIDISING AGENT
REDUCING agent
GANGUE
flux

Answer :D
Discussion
23.

Calcium carbonate reacts with aqueous HCl according to the reaction : CaCO_(3)(s)+2HCl(aq) rarr CaCl_(2)(aq)+CO_(2)(g)+H_(2)O(l). What mass of CaCO_(3) is required to react completely with 25 mL of 0.75 M HCl ?

Answer»

SOLUTION :Step 1. To calculate mass of HCl in 25 mL of 0.75 M Hcl
1000 mL of 0.75 M HCl contains HCl = 0.75 moles `=0.75xx36.5g=24.375g`
`therefore"25 mL of 0.75 HCl will contain HCl"=(24.375)/(1000)xx25g=0.6844g.`
Step 2. To calculate mass of `CaCO_(3)` reacting completely with 0.9125 G of HCl
`CaCO_(3)(s)+2HCl(aq) rarr CaCl_(2)(aq)+CO_(2)(g)+H_(2)O(l)`
2 moles of HCl, i.e., `2xx36.5 g=73g HCl` REACT completely with `CaCO_(3) = "1 MOLE = 100 g"`
`therefore " 0.6844 g HCl will react completely with "CaCO_(3)=(100)/(73)xx0.6844g=0.938g`
Discussion
24.

Calcium carbonate is naturally available as limestone and can also be synthesized from quick lime. It is seen that the compositions of the elements in both the natural and synthetic calcium carbonate are same. The validity of which one among the following lawsis confirmed by this observation ?

Answer»

LAW of conservation of mass
Low of definite proportion
Law of MULTIPLE proportion
Avogadro's law

Solution :ACCORDING to law of definite proportion, a chemical COMPOUND is always found to be made up of the same element COMBINED together in the same fixed proportion by mass.
Discussion
25.

Calcium carbonate decomposes completely. On heating into lime (CaO) and carbon dioxide (CO_(2)). 1kg of calcium carbonate is completely decomposed by heat, when 560gof lime are obtained. How much quantity of carbon dioxide in grams, moles and litres at NTP is produced in the process?

Answer»

Solution :According to law of conservation of mass,
mass of lime+ Mass of carbon dioxide=Mass of calcium
560g+mass of `CO_(2)=1000g`
Molecular mass of `CO_(2)=12+32=44g` (1 mole)
No. of MOLES in 440 G of `CO_(2)=(440)/(44)=10`
1 mole of `CO_(2)` occupies volume at NTP=22.4 LITRE
10 moles `CO_(2)` will occupy volume at NTP
`=22.4xx10=224` litre.
Discussion
26.

Calcium carbide when heated with nitrogen forms:

Answer»

`Ca_3N_2`
`CA(CN)_2`
`CaCN_2`
`Ca(CNO)_2`

ANSWER :C
Discussion
27.

Calcium carbide reacts with nitrogen to give

Answer»

CaCN
`Ca(CN)_(2)`
`N_2O`
`NO_(2)`

ANSWER :B
Discussion
28.

Calcium carbide on reacting with water gives

Answer»

Methane
Ethane
Ethene
ACETYLENE

Solution :`CaC_2+2H_2O to UNDERSET"Acetylene"(CH-=CH)+CA(OH)_2`
Discussion
29.

Calciumburns innitrogento produce a whitepowder whichdissolveinsufficientwaterto produce a gas A and analkline solution .The solutionon esposureto air produces a thissolidlayer of Bon the surface identifythecompound A and B.

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Solution :A is ammonia and B is calcuimcarbonate
`CA+N_(2) rarr underset("White powder")(Ca_(3)N_(2))`
`Ca_(#) +H_(2)O rarr Ca(OH)_(2) +underset((A))(NH_(3))`
`Ca(OH)_(2) OVERSET(COO_(2))rarr underset((B))(CaCO_(3))+H_(2)O`
Discussion
30.

Calcium bums in nitrogon to produce a white powder which dissolves in sufficient water to produce a gas (A) and an alkaline solution. The solution on exposure to air produces a thin solid layer of (B) on the surface. Identify the compounds A and B.

Answer»

Solution :`NH_(3),CaCO_(3)`
`3Ca+N_(2)toCa_(3)N_(2)overset(6H_(2)O)tounderset(Alkali)(Ca(OH)_(2))+underset(A)(2NH_(3))`
`Ca(OH)_(2)overset(CO_(2))tounderset(SOLID)(CaCO_(3))+H_(2)O`
Discussion
31.

Calcium ammonium nitrate (CAN) is a popular nitrogen fertilization because it is

Answer»

slow supplier of nitrogen
having more percentage of nitrogen in it.
fixing the nitrogen in the soil
capable of making the soil acidic.

Solution :Calcium ammoium nitrate (CAN) FERTILIZER is almost neutral and can be safely applied even to acid soils. Its total nitrogen (N) CONTENT is higher and may vary from 25 to 28% N content. Half (12.5% N) of this total nitrogen is in the ammonical FORM and rest half (12.5% N) in nitrate form . this is a good FERTILIZERS applied in Agriculture.
Discussion
32.

Calcium formate on heating forms _____.

Answer»

`CO_2, H_2O`
`CH_3CHO`
`HCHO`
`CH_3COCH_3`

SOLUTION :ACETALDEHYDE
Discussion
33.

Name the product formed when calcium acetate is heated with calcium formate.

Answer»

SOLUTION :ACETALDEHYDE
Discussion
34.

Calcium acetate to acetaldehyde

Answer»

Solution :Calcium ACETATE to acetaldehyde
`UNDERSET("Calcium acetate")((CH_(3)COO)_(2)Ca)+underset("Calcium FORMATE")((HCOO)_(2)Ca) underset("dry distillation")(overset("heat")to ) underset("Acetaldehyde")(2CH_(3)CHO+2CaCO_(3))`
Discussion
35.

Calcium Acetate on heating under distillation gives

Answer»

Acetaldehyde and CALCIUM oxide
Calcium CARBONATE and Acetic acid
Acetone and Calcium carbonate
Calcium oxide and `CO_(2)`

Solution :Dry distillation of calcium salts of fatty acids other than FORMIC acids gives KETONES.
`(RCOO)_(2)CA overset(Delta)rarr RCOR + CaCO_(3)`
Discussion
36.

Calcium acetate on heating gives

Answer»

acetone
FORMIC ACID
ACETAL dehyde
methane

ANSWER :A
Discussion
37.

Calcium acetate , on dry distillation with calcium formate gives :

Answer»

Acetaldehyde
Formaldehyde
Aceton
All

Answer :D
Discussion
38.

Calcium acetate on dry distillation gives .............

Answer»

ACETIC acid
PROPANONE
ETHANOL
PROPANAL

SOLUTION :Propanone
Discussion
39.

Calcite is example of .......... system.

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RHOMBOHEDRAL 
TETRAGONAL 
TRICLINIC 
ORTHORHOMBIC 

ANSWER :A
Discussion
40.

Calcium acetate on distillationn gives :

Answer»

ACETONE
ACETIC acid
Acetaldehyde
Formaldehyde.

Solution :
Discussion
41.

Calcite belongs to

Answer»

TETRAGONAL SYSTEM
TRIGONAL system
Digonal system
Hexoagonal system

SOLUTION : It is a FACT.
Discussion
42.

Calcinations is carried out in a :

Answer»

Blast furnace
ELECTRIC furnace
Bessemer CONVERTOR
REVERBERATORY furnace

Answer :D
Discussion
43.

The role of calcinationin metallurgical operations is:

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MAGNESITE ore
Dolomite ore
Malachite ore
All

Answer :D
Discussion
44.

Calcination is used in the metallurgy of:

Answer»

MAGNESITE ore
Dolomite ore
Malachite ore
All

Answer :D
Discussion
45.

Calcination of an ore means :

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STRONG HEATING in presence of AIR
Strong heating in the absence of air
Strong heating only to melt the ore
Strong heating in the reducing - oxidising sphere

Answer :C
Discussion
46.

Calcination is used in metallurgy for removal of

Answer»

water and sulphide
water and `CO_(2)`
`H_(2)O and H_(2)S`
water and `CO_(2) and H_(2)S`

SOLUTION :Calcination is the process which is used in METALLURGY for removal of VOLATILE impurities like water and `CO_(2)`
Discussion
47.

Calcinationistheprocess ofheatingthe orestronglyin the………….. ofair.

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ANSWER : absenceor LIMITED SUPPLY
Discussion
48.

Calcination is the process of heating the ore :

Answer»

in INERTGAS
in thepresenceofair
in theabsenceof air
in thepresenceofCaOandMgO

Answer :C
Discussion
49.

Calcination is the peccess of heating the ore

Answer»

`Cu_(2)O+FeS`
`FeSiO_(3)`
`CuFeS_(2)`
`Cu_(2)S+FeO`

Answer :B
Discussion
50.

Calcination is a thermal treatment process of ores which can not bring :

Answer»

Thermal decomposition
phase TRANSITION of impurities
Removal of volatile FRACTIONS like `CO_(2) , H_(2)O`
MELTING of the solid ore

Answer :D
Discussion