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701.

In reaction of hydrogen peroxide and sodium carbonate, `H_2O_2` acts as____.A. Oxidising agentB. Reducing agentC. Bleaching agentD. Both oxidising and bleaching agent

Answer» Correct Answer - B
`H_(2)O_(2)` acts as a reducing agent in the reaction between `O_(3)` and `H_(2)O_(2)`
702.

Which of the following sets of compounds correctly ltbr. Illustrate the law of reciprocal proportions?A. `P_(2)O_(3),PH_(3), H_(2)O`B. `P_(2)O_(5),PH_(3), H_(2)O`C. `N_(2) O_(5),NH_(3), H_(2)O`D. `N_(2) O,NH_(3), H_(2)O`

Answer» Correct Answer - A
`P_(2) O_(3), PH_(3) and H_(2) O ` illustrates the law of reciprocal
proportions, Ratio in the number of atoms of H and O
combinig with one P is 3, i.e., `2 : 1`.
703.

The percentage of hydrogen in water and hydrogen peroxide is 11 .1 and 5.9 respectively . These figures illustrateA. Law of multiple proportionsB. Law of conservation of massC. Law of constant proportionsD. Law of combining volumes

Answer» Correct Answer - A
704.

An element forms two oxides containing respectively `53.33` and `36.36` percent of oxygen. These figures illustrate the law ofA. (a)Conservation of massB. (b)Constant proportionsC. (c )Reciprocal proportionsD. (d)Multiple proportions

Answer» Correct Answer - D
705.

Number of hydrogen ions present in 10 millionth part of `1.33 cm^(3)` of pure water at `25^(@)C` isA. 6.023 millionB. 60 millionC. 8.01 millionD. 80.23 million

Answer» Correct Answer - C
Now `[H^(+)]=10^(-7)` mole/litre
Now 1000 ml contains `10^(-7)` mole `H^(+)`
1 ml contains `10^(-7)/1000` mole `H^(+)`
`1.33xx10^(-7)` ml - contains `1.33xx10^(-17)` 10 million `=10^(-7)` so, `10 "million"^(th)` part of `1.33 cm^(3)=1.33xx10^(-7)` ml
so, no. of `H^(+)` ions `=1.33xx10^(-17)xxN_(A)`.
706.

The mass of `CaCO_(3)` produced when carbon dioxide is bubbled through 500 mL of `0*5 M` `Ca(OH)_(2)` will beA. 10 gB. 20 gC. 50 gD. 25 g

Answer» Correct Answer - D
`Ca(OH)_(2)+CO_(2)toCaCO_(3)+H_(2)O`
`Ca(OH)_(2) = 0*5xx500xx10^(-3)` moles
`=0*25` mol
Now 1 mole `Ca(OH)_(2)` gives `CaCO_(3) = 100g`
`0*25` mole `Ca(OH)_(2)` gives `CaCO_(3)`
`=0*25xx100=25g`
707.

If `CO_(2)` gas is passed through 500 ml of `0.5 (M) Ca(OH)_(2)`, the amount of `CaCO_(3)` produced isA. 10 gB. 20 gC. 50 gD. 25 g

Answer» Correct Answer - D
By equating the equivalents
`W/100xx2=(500xx0.5xx2)/1000`
`W=25 g" "(W="mass of "CaCO_(3))`
708.

If 500mL of a 5M solution is diluted to 1500 mL, what will be the molarity of the solution obtained?A. 1.5 MB. 1.66 MC. 0.017 MD. 1.59 M

Answer» `M_1V_1 = M_2V_2`
`5Mxx500mL = M_2xx1500mL`
`therefore M_2=(5xx500)/(1500)=1.66M`
709.

The empirical formula of an acid is `CH_(2)O_(2)`, the probable molecular formula of acid may beA. (a)`CH_(2)O`B. (b)`CH_(2)O_(2)`C. (c )`C_(2)H_(4)O_(2)`D. (d)`C_(3)H_(6)O_(4)`

Answer» Correct Answer - c
Empirical formula of an acid is `CH_(2)O_(2)`
`("Empirical formula")_(n)` = Molecular formula
n= whole no. multiple i.e. 1, 2, 3, 4.
If n=1 molecular formula `CH_(2)O_(2)`.
710.

The empirical formula of an acid is `CH_(2)O_(2)`, the probable molecular formula of acid may beA. `CH_(2)O`B. `CH_(2)O_(2)`C. `C_(2)H_(4)O_(2)`D. `C_(4)H_(6)O_(4)`

Answer» Correct Answer - B
M. Formula = n(E. Formula)
where n = 1,2,3, etc
711.

How many meteres are equivalent to `5.00` in?A. `12.7 m`B. `127m`C. `0.127m`D. `1.27m`

Answer» Correct Answer - C
Use the relations 1 in `= 2.54 cm` and `4 cm = 10^(-2) m`.
Follow the sequence in `rarr cm rarr m`
`(5.00 "in".) xx ((2.54 cm)/(1 "in".)) xx ((1xx10^(-2)m)/(1 cm))`
712.

The density of a gas A is thrice that of a gas B at the same temperature. The molecular weight of gas B is twice that of A. What will be the ratio of the pressure acting on B and A?A. (a)`1/4`B. (b)`7/8`C. (c )`2/5`D. (d)`1/6`

Answer» Correct Answer - d
`d=(PM)/(RT)`
`implies d_(A)/d_(B)=(P_(A)M_(A))/(P_(B)M_(B))` T is same
`d_(A)=3d_(B)`
`M_(B)=2M_(A)` or `M_(A)=M_(B)/2`
`implies (3d_(B))/d_(B)=P_(A)/P_(B)xxM_(B)/(2xxM_(B))`
`P_(B)/P_(A)=1/6`.
713.

Vapour density of a gas is 22. What is its molecular mass?A. `33`B. `22`C. `44`D. `11`

Answer» Correct Answer - C
M. Mass `= 2xxV.D. = 2xx22 = 44`
714.

The vapour density of gas A is four times that of B. If moelcular mass of B is M, then molecular mass of A isA. MB. 4 MC. `(M)/(4)`D. 2 M

Answer» Correct Answer - B
Molecular mass of B = M
V.D. of B = M/2
V.D. of A `= 4xxV.D.` of B `= 4xxM//2=2M`
Molecular mass of `A = 2xx2M = 4M`
715.

The vapour density of a gas A is twice that of a gas B. If the molecular weight of B is M, the molecular weight of A will be:A. (a)MB. (b)2MC. (c )3MD. (d)M/2

Answer» Correct Answer - B
`("Vapour density of A")/("Vapour density of B")=("molar mass of A")/("molar mass of B")`
Molar mass of `A=2xxM/1`
716.

How many grams are equivalent to `66 Ib` (pound) of sulphur?A. `20000`B. `30000`C. `40000`D. `25000`

Answer» Correct Answer - B
Use the relations 1 pound `= 0.454 kg` and `1 kg = 1000g`.
Follow the sequence `lb rarr kg rarr g`
`(66 Ib) ((0.454 kg)/(1 lb)) ((1000 g)/(1 kg))`
717.

The total charge (coulombs) required for complete electrolysis isA. 24125B. 48250C. 96500D. 193000

Answer» `Na^(+) + e^(-) to Na`
Moles of `Na^+` discharged at cathode =2
`therefore` The no. of electrons required for this purpuse = 2 moles
`therefore` Total charge required = 2 faradays `=2xx96500`
=193000 coulombs.
718.

The charge in coulombs on 1 g ion of `N^(3-)` isA. (a)`5.2xx10^(6) C`B. (b)`2.894xx10^(5) C`C. (c )`6.6xx10^(6) C`D. (d)`8.2xx10^(6) C`

Answer» Correct Answer - B
One ion carries `3xx1.6xx10^(-19)` coulombs
Then `1 g` ion `N^(3-)(1 "mole")` carries
`=3xx1.6xx10^(-19)xx6.2xx10^(23)=2.89xx10^(5)` coulombs
719.

The speed limit on a highway is 55 mile `h^(-1)`. Express this speed in `SI` base units.A. `25 ms^(-1)`B. `35 ms^(-1)`C. `20 ms^(-1)`D. `30 ms^(-1)`

Answer» Correct Answer - A
Use the relations `1 ft = 12 In`.
`1 "mile" = 5280 ft, 1 "in" = 2.54xx10^(-2) m`, and `1 h = 3600 s`
`"mile" rarr ft rarr "in" rarr m` and `h rarr s`
`(55 ("mile")/(h)) ((580 ft)/(1 "mile")) ((12 "in.")/(1 ft.)) ((2.54xx10^(-2) m)/(1 "in")) ((1h)/(3600 s))`
`= 25 m s^(-1)`
720.

The law of conservation of mass is not obeyed by aA. redox reactionB. double decomposition reactionC. nuclear reactionD. neutralization reaction

Answer» Correct Answer - C
Because a nuclear reaction is not a chemical reaction.
721.

The atomic weights of two alements A and B are 40 and 80 reapectively. If x g of A contains y atoms, how many atoms are present in 2x g of B?A. (a)`y/2`B. (b)`y/4`C. (c )yD. (d)2y

Answer» Correct Answer - C
`{:(,,A,,B),("Atomic mass",,40,,80),("given weight",,x "gram",,2x "gram"),("No. of mole",,x/40,,(2x)/80),("No. of atom",,x/40xxN_(A),,x/40xxN_(A)),("But according to question",=,x/40xxN_(A)=y,,):}`
722.

Formation of CO and `CO_(2)` illustrates the law ofA. Conservation of massB. multiple proportionC. reciprocal proportionD. constant proportion

Answer» b) Formation of CO and `CO_(2)` illustrates the law of multiple proportion.
723.

A purified cytochrome protein was found to contain 0.376 % iron. What is the minimum molecular mass of the protein?A. `14,800 u`B. `1480 u`C. `148,000 u`D. `148 u`

Answer» Correct Answer - A
Mass of iron (minor component) per gram of protien `=(0.376)/(100)=0.00376g`
Atomic mass of iron = 56 u
Minimum molecular mass
`=("Atomic mass of Fe")/("Mass of Fe per gram of macromolecule")`
`(56)/(0.00376)=14,800 u`
724.

Oxidation number of oxygen in ozone `(Q_(3))` isA. `+3`B. `-3`C. `-2`D. 0

Answer» Correct Answer - D
Molecule and free atoms show zero oxidation state `O_(3)` is a molecule shows zero oxidation state.
725.

Oxidation state of oxygen inhydrogen peroxide isA. `-1`B. `+1`C. `0`D. `-2`

Answer» Correct Answer - A
In all peroxide shows -1 oxidation state.
726.

Oxygen has an oxidation state of +2 inA. `H_(2)O_(2)`B. `CO_(2)`C. `H_(2)O`D. `OF_(2)`

Answer» Correct Answer - D
Oxygen have +2 oxidation state in `OF_(2)`.
727.

The sum of the oxidation numbers of all the carbons in `C_(6)H_(5)CHO` isA. `+2`B. 0C. `+4`D. `-4`

Answer» Correct Answer - D
In benzaldehyde all carbon atoms show -4 oxidation state.
728.

The number of mole of `KMnO_(4)` that will be needed to react completely with one mole of ferrous oxalate in acidic solution is:A. (a)`0.6` moleB. (b)`0.4` moleC. (c )`7.5` moleD. (d)`0.2` mole

Answer» Correct Answer - a
In ferrous oxalate ferrous and oxalate ions are oxidized.
`Fe^(2+) rarr Fe^(3+)+e^(-)`
`C_(2)O_(4)^(2-) rarr 2CO_(2)+2e^(-)`
`MnO_(4)^(2-) rarr Mn^(2+)`
Thus eqn. will be `3MnO_(4)^(-)+5FeC_(2)O_(4) rarr`
`implies` 1 mole of ferrous oxalate requires `3//5` moles of `KMnO_(4)`, i.e., 0.6 mole.
729.

The number of moles of `KMnO_(4)` that will be needed to react completely with one mole of ferrous oxalate in acidic solution is:A. `3/5`B. `2/5`C. `4/5`D. `1`

Answer» Correct Answer - A
`FeC_(2)O_(4) hArr Fe^(2+) + C_(2)P_(4)^(2-) : MnO_(4)^(-) " oxidises " Fe^(2+) and C_(2)O_(4)^(2-)` both
`F^(2+) + C_(2)O_(4)^(2-) rarr Fe^(3+) + 2CO_(2) + 3e^(-) , MnO_(4)^(-) + 5e^(-) rarr Mn^(2+) , 5Fe C_(2)O_(4) -= 3MnO_(4)^(-) or 1 Fe C_(2)O_(4) -= (3)/(5) MnO_(4)^(-)`
730.

If 8.5 g of hexane burns completely in oxygen, how many moles of `CO_(2)` is/are produced?A. 6B. 0.6C. 0.9D. 1.2

Answer» `C_(6)H_(12)+9O_(2)to6CO_(2)+6H_(2)O`
`6xx12+12=84`
`because`84g`C_(6)H_(12)`gives=6moles of `CO_(2)`
`therefore 8.4 g C_(6)H_(12)` will give `=(6xx8.4)/(84)`=0.6`mole of `CO_(2)`
731.

19.7 kg of gold was recovered from a smuggler. How many atoms of gold were recovered?A. 100B. `6.02 xx 10^(23)`C. `6.02 xx 10^(24)`D. `6.02 xx 10^(25)`

Answer» Atoms recovered `=(19700)/(197)xxN_(A)`
`=100xx6.02xx10^(23)=6.02xx10^(23)`
732.

1 mol of `CH_(4)` containsA. (a)`6.02xx10^(23)` atoms of `H`B. (b)`4 g` atom of HydrogenC. (c )`1.81xx10^(23)` molecules of `CH_(4)`D. (d)`3.0 g` of carbon

Answer» Correct Answer - B
1 mole of `CH_(4)` contains `4` mole of hydrogen atom, i.e., `4 g` atom of hydrogen.
733.

The oxygen obtained form 72 kg of water isA. 72 kgB. 46 kgC. 50 kgD. 64 kg

Answer» Correct Answer - D
The oxygen obtained from 72 kg of water is obtained by the following equation.
`{:(2H_(2)O,rarr,2H_(2),+,O_(2)),(2(2+16)=36,,,,(2xx16)=32):}`
Therefore, 36 kg of water produce 32 kg of oxygen.
Hence, `72` kg of water produce oxygen
`=(32xx72)/36=64` kg.
734.

In order to prepare one litre normal solution of `KMnO_(4)`, how many grams of `KMnO_(4)` are required if the solution is used in acidic medium for oxidationA. 158 gB. 31.6 gC. 790 gD. 62 g

Answer» Correct Answer - B
Acidic medium `E=M/5=158/5=31.6` gm.
735.

In order to prepare one litre normal solution of `KMnO_(4)`, how many grams of `KMnO_(4)` are required if the solution is used in acidic medium for oxidationA. (a)`158 g`B. (b)`31.6 g`C. (c )`790 g`D. (d)`62 g`

Answer» Correct Answer - B
Acidic medium `E=M/5=158/5=31.6 g`.
736.

On reduction with hydrogen, `3.6 g` of an oxide of matel left `3.2 g` of metal. If the vapour density of metal is `32`, the simplest formula of the oxide would beA. `MO`B. `M_(2)O_(3)`C. `M_(2)O`D. `M_(2)O_(5)`

Answer» Correct Answer - C
As we know that
Equivalent weight `=("weight of metal")/("weight of oxygen")xx8`
`=3.2/0.4xx8=64`
Vapour density `=("mol. wt")/2`
Mol. Wt`=2xxV.D=2xx32=64`
As we know that `n=("mol. wt")/("eq. wt")=64/64=1`
Suppose, the formula of metal oxide be `M_(2)O_(n)`. Hence the formula of metal oxide `=M_(2)O`.
737.

The most abundant elements by mas in the body of a healthy human adult are Oxygen `(61.4%)`, Carbon `(22.9%)`. Hydrogen `(10.0)%)`, and Nitrogen `(2.6%)`. The weight which a `75 kg` person would gain if all `.^(1)H` atoms are replaced by `.^(2)H` atoms isA. 15 kgB. 37.5 kgC. 7.5 kgD. 10 kg

Answer» Correct Answer - C
Given, abundance of element by mass
oxygen `= 61.4 %` carbon `= 22.9%` hydrogen `= 10%` and nitrogen `= 2.6%`
Total weight of person `= 75 kg`
Mass due to `.^(1)H = (75 xx 10)/(100) = 7.5 kg`
`.^(1)H` atoms are replaced by `.^(2)H` atoms,
Mass due to `.^(2)H = (7.5 xx 2) kg`
`:.` Mass gain by person `= 7.5 kg`
738.

The most abundant elements by mas in the body of a healthy human adult are Oxygen `(61.4%)`, Carbon `(22.9%)`. Hydrogen `(10.0)%)`, and Nitrogen `(2.6%)`. The weight which a `75 kg` person would gain if all `.^(1)H` atoms are replaced by `.^(2)H` atoms isA. 37.5 kgB. 7.5 kgC. 10 kgD. 15 kg

Answer» Correct Answer - B
75 kg person contain 10% hydrogen i.e. 7.5 kg Hydrogen.
If all H atom are replaced by `.^(2)H`, the weight of Hydrogen become twice i.e., it increased by 7.5 kg
739.

What volume of oxygen gas `(O_(2))` measured at `0^(@)C` and 1 atm is needed to burn completely `1 L` of propane gas `(C_(3)H_(8))` measured under the same condition?A. `5L`B. `10L`C. `7L`D. `6L`

Answer» Correct Answer - A
`{:(C_(3)H_(8),+,5O_(2),to,3CO_(2),+,4H_(2)O),("Propane",,,,,,),(1vol,,5vol,,3vol,,4vol):}`
According to the balanced equation , one volume of 1 L propane needs 5 volumes or 5L of `O_(2)` for complete combustion
740.

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will beA. `3mol`B. `4mol`C. `1mol`D. `2mol`

Answer» Correct Answer - B
`10g H_(2) = (10)/(2)=5` mol,
64 g of `O_(2) = (64)/(32) = 2` mol
`{:(H_(2),+,(1)/(2)O_(2),to,H_(2)O),(1mol,,0.5mol,,1mol),(5mol,,2.5mol,,5mol),(,,2mol,,?):}`
In 5 mol of oxygen needed = 2.5 mol which not present `:. O_(2)` is the limiting reactant. Hence `H_(2)O` formed from 2 mol is 4 mol.
741.

If we consider that `1/6` in place of `1/12`, mass of carbon atom is taken to be the relative atomic mass unit, the mas of one mole of a substance willA. decrease twiceB. increase two foldC. remain unchangedD. be a function of the molecular mass of substance

Answer» Correct Answer - C
1 mole = No. of atoms in 12.0000 g of `C^(12) = 6.022xx10^(23)`
Mass of 1 mole of a substance = Actual mass of 1 atom (or molecule) of the substanc `xx6.022xx10^(23)`
As mass of 1 mole of substance does not depend upon the atomic mass unit scale, the mass of one mole of substance will not change
742.

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by Hall process isA. `180 kg`B. `270 kg`C. `540 kg`D. `90 kg`

Answer» Correct Answer - D
`2Al_(2)O_(3)+underset(3xx12g)(3C)to3CO_(2)+underset(4xx27g)(4Al)`
`4xx27g` of Al are obtained when carbon anode consumed `= 12xx3 g`
743.

If 30 mL of `H_(2)` and 20 mL of `O_(2)` reacts to form water, what is left at the end of the reaction?A. 10 mL of `H_(2)`B. 5 mL of `H_(2)`C. 10 mL of `O_(2)`D. 5 mL of `O_(2)`

Answer» Correct Answer - D
`underset(2vol)(2H_(2))+underset(1vol)(O_(2))to2H_(2)O`
2 mole of `H_(2)` reacts with 1 vol of `O_(2)` to give water. Therefore, 30 mL of `H_(2)` will reacts with 15 mL of `O_(2)` to give water. Here, `H_(2)` is the limiting reactant.
Volume of `O_(2)` left unreacted = 20-15=5 mL
744.

How will you separate a solution (miscible) of benzene + `CHCl_(3)`?A. SublimationB. FiltrationC. DistillationD. Crystallisation

Answer» Correct Answer - C
Boiling points of benzene and chloroform are `80^(@)C` and `61.5^(@)C` respectively. As such they can be separated by fractional distillation
745.

Two elements X and Y combine in gaseous state to form XY in the ratio `1:35*5` by mass. The mass of Y that will be required to reat with 2 g of X isA. `7*1 g`B. `3*55 g`C. `71 g`D. `35*5 g`

Answer» Correct Answer - C
1 g of X combines with Y `= 35*5 g`
`:.` 2 g of X combines with Y `= 2xx35*5 = 71 g`
746.

Two compounds A and B have some percentage composition. The compouds A and BA. are identicalB. are isomersC. are neither identical nor isomersD. All the three are correct

Answer» Correct Answer - D
Converse of law of definite proportion is not true. For example, butane and isobutane have same percentage composition (Choice B), acetylene, `C_(2)H_(2)` and benzene, `C_(6)H_(6)` have same percentage composition. As such choice (D) is correct
747.

Which of the following has the smallest number of molecules?A. 0.1 mol of `CO_(2)` gasB. 11.2 L of `CO_(2)` gas at N.T.P.C. 22 g of `CO_(2)` gasD. `22.4xx10^(3)mL` of `CO_(2)` gas

Answer» Correct Answer - A
0.1 mol `CO_(2), (11.2)/(22.4) = 0.5 mol CO_(2),`
`(22)/(44) = 0.5 mol CO_(2), (22400)/(22400) = 1 mol CO_(2)`
748.

Among the species given below which have same number of molecules?A. 3.2 g of `O_(2)`B. 0.1 mol of `NH_(3)`C. 4.0 g of `He`D. 11.2 L of `Cl_(2)` at S.T.P.

Answer» Correct Answer - A::B::D
Same number of molecules are present in 3.2 g of `O_(2)` (0.1 mol) and 0.1 mol of `NH_(3)`.
749.

A solution is prepared by dissolving 5.3 g of `Na_(2)CO_(3)` in 250 `cm^(3)` of solution. The solution can be described asA. Decinormal solutionB. Decimolar solutionC. 0.4 N solutionD. 0.2 M solution

Answer» Correct Answer - C::D
Mol. Mass of `Na_(2)CO_(3)=106`
Eq. mass of `Na_(2)CO_(3)=106//2=53`
Molarity `=(5.3xx1000)/(106xx250)=0.2M`
Normality `=(5.3xx1000)/(53xx250)=0.4N`
750.

What is the mass of the precipitate formed when 50 mL of 16.9% solution of `AgNO_(3)` is mixed with 50 mL of 5.8% NaCl solution?A. (a)`7 g`B. (b)`14 g`C. (c )`28 g`D. (d)`3.5 g`

Answer» Correct Answer - a
`16.9 g AgNO_(3)` is present in `100 mL` solution.
`:. 8.45 g AgNO_(3)` is present in `50 mL` solution.
` 5.8 g NaOl` is present in `100 mL` solution.
`:. 2.9 g NaCl` is present in `50 mL` solution.
`AgNO_(3)+NaCl rarr AgCl+ NaNO_(3)`
`8.45/170 mol" " 2.9/58.5`
`=0.049 mol=0.049 mol rarr 0" " 0`
`After "0 " 0 rarr 0.049 mol 0.049`
reaction" " mol
Mass of `AgCl` precipitated
`=0.049xx143.5 g =7 g AgCl`.