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The most abundant elements by mass in the body of a healthy human adult are : Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight (in kg) which a 75 kg person would gain if all ^{1}H atoms are replaced by ^{2}H atoms is :  
Option: 1 7.5
Option: 2 10
Option: 3 15
Option: 4 37.5
 

Given that

Mass of the person = 75 kg

Mass of 1H1 present in person = 10% of 75 kg = 7.5 kg

Since Mass of 1H2 is double the Mass of 1H1

So, Mass of 1H2 will be in person = 2 X 7.5 kg =15 kg

Thus, increase in weight = 15 - 7.5 = 7.5 kg

Therefore, Option (1) is correct

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Posted by

vishal kumar

The correct order of the atomic radii of C, Cs, Al and S is :
Option: 1 S<C<Cs<Al
Option: 2 C<S<Al<Cs
Option: 3 C<S<Cs<Al
Option: 4 S<C<Al<Cs
 

 

Periodicity of atomic radius and ionic radius in period -

In a period from left to right the effective nuclear charge increases because the next electron fills in the same shell. So the atomic size decrease.

- wherein

Li>Be>B>C>N>O>F

 

 

 

Electronegativity and atomic radius -

The attraction between the outer electrons and the nucleus increases as the atomic radius decreases in a period.

- wherein

Electronegativity\propto\frac{1}{atomic\:radius}

 

 

 

Size of atom and ion in a group -

In a group moving from top to the bottom the number of shell increases.So the atomic size increases.

- wherein

Li<Na<K<Rb<Cs

As we know that

From Left to right in a period size decreases and when going down the group size increases

C< S< Al< Cs

Therefore, Option(2) is correct

  

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Posted by

Ritika Jonwal

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The IUPAC symbol for the element with atomic number 119 would be:
Option: 1 uue
Option: 2une
Option: 3 unh
Option: 4 uun

 

Nomenclature of elements with atomic number >100 -

The name is derived directly from the atomic number of the element using the following numerical roots:

0 = nil

1 = un

2 = bi

3 = tri

4 = quad

5 = pent

6 = hex

7 = sept

8 = oct

9 = enn

Eg:

 

Atomic number

Name

Symbol

101

Mendelevium (Unnilunium)

Md (Unu)

102

Nobelium (Unnilbium)

No (Unb)



 

-

uue

1  1  9

Un Un ennium

Therefore, Option(1) is correct.

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Posted by

Ritika Jonwal

The ammonia (NH_{3}) released on quantitative reaction of 0.6g, urea (NH_{2}CONH_{2}) with sodium hydroxide (NaOH) can be neutralised by:
Option: 1 200 ml of 0.2 N HCl
Option: 2200 ml of 0.4 N HCl
Option: 3100 ml of 0.1N HCl
Option: 4100 ml of 0.2N HCl
 

2 × mole of Urea = mole of NH_{3} ........(1)
mole of NH_{3} = mole of HCl ........(2)
\therefore mole of HCl = 2 × mole of Urea

mole of HCl =2\times \frac{0.6}{60}=0.02mol ...(i)

[We know , mole = M X V = N X n X V]

 \mathrm{100 \ ml\times 0.2N\times 1=0.02\ mol} ...as (i).

Therefore, Option(4) is correct.

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Posted by

Ritika Jonwal

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Mischmetal is an alloy consisting mainly of :
Option: 1 lanthanoid metals
Option: 2 actionoid and transition metals
Option: 3 Lanthanoid and actionoid metals
Option: 4 actionoid metals

Mischmetal is an alloy of lanthanoid metals with Fe.

It consists of a lanthanoid metal (~95%) and iron (~5%) and traces of S, C, Ca, and Al.

Therefore, the correct option is (1).

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Posted by

Kuldeep Maurya

The average molar mass of chlorine is 35.5\: g\: mol^{-1}. The ratio of ^{35}Cl\; to\; ^{37}Cl in naturally occurring chlorine is close to :  
Option: 1 4:1
Option: 2 3:1
Option: 3 2:1
Option: 4 1:1

Given,

The average molar mass of chlorine is 35.5\: g\: mol^{-1}.

 

Let , the ratio of ^{35}Cl\; to\; ^{37}Cl in naturally occurring chlorine is close to x : y

 

Now, we know

\text { Av. molar mass }=\frac{\mathrm{n}_{1} \mathrm{M}_{1}+\mathrm{n}_{2} \mathrm{M}_{2}}{\left(\mathrm{n}_{1}+\mathrm{n}_{2}\right)}

So, 

35.5=\frac{x \times 35+y \times 37}{x+y}

1.5 y=-0.5 x

\frac{x}{y}=\frac{3}{1}

Therefore, the correct option is (2).

 

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Posted by

Kuldeep Maurya

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The minimum number of moles of O2 required for complete combustion of 1 mole of propane and 2 moles of butane is ______
 

Combustion reaction of 1 mole of propane and 2 moles of butane-

 

So, Total required mol of O2 = 5 + 13 = 18.

Ans = 18

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Posted by

Kuldeep Maurya

If a person is suffering from the deficiency if nor-adrenaline, what kind of drug can be suggested ?  
Option: 1 Anti-inflammatory
Option: 2 Antidepressant
Option: 3 Antihistamine
Option: 4 Analgesic

Non-adrenaline is a neurotransmitter. If nor-adrenaline is low, a person may suffer from depression. Hence, an antidepressant drug is suggested.

Anti-depressant → drug, which enhances the mood.

Therefore, the correct option is (2).

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Posted by

Kuldeep Maurya

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The following molecules act as an :
Option: 1 Antidepranant
Option: 2 Anti-bacterial  
Option: 3 Antiseptic
Option: 4 Anti-histamine

Brompheniramine works by blocking the action of histamine, which causes allergic symptoms.

Hence, it acts as an antihistamine.

Therefore, Option(3) is correct.

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Posted by

Kuldeep Maurya

The mass of ammonia in grams produced when 2.8 kg of dinitrogen quantitatively reacts with 1 kg of dihydrogen is_________
Option: 1 3400
Option: 2 -
Option: 3 -
Option: 4 -

Given,

2.8 kg of dinitrogen quantitatively reacts with 1 kg of dihydrogen.

From above, the mole of ammonia = 0.2 kMol

So, mass of ammonia = mole X molar mass

mass of ammonia = 0.2 (kMol ) X 17 (g/Mol) 

mass of ammonia = 3.4 kg = 3400 g

Ans = 3400

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Posted by

Kuldeep Maurya

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