Test: CSIR-NET Chemical Sciences Mock Test - 8 - CSIR NET Chemical Science MCQ

• Sugar unit present in DNA is derived from Deoxyribose.
• The DNA molecule is a polymer of nucleotides. Each nucleotide is composed of a nitrogenous base, a five-carbon sugar i.e. Deoxyribose, and a phosphate group.

So, option A is the right answer.

The Threshold Frequency is the minimum frequency of radiation that will produce a photoelectric effect.

• Einstein explained this discrepancy in 1905 with a theory that light carried discrete packets of energy called “quanta” (now “photons”) and that each “quantum” has an energy EE, which is related to its frequency νν by the Planck (or Planck-Einstein) Relation: E=hνE=hν.
• He won the Nobel Prize for this work.

3 years hence, son’s age = 15
Therefore, present age of son=15-3 = 12 years
Person present age= present age of son * 4 =12*4 = 48 years
Wife present age= Person present age -3 = 48-3 = 45 years
After 5 years’ person wife’s age = 45 + 5 = 50 years.

A terrestrial ecosystem is an ecosystem found on landforms only.
The primary terrestrial ecosystems are tundra, taiga, temperate deciduous forest, grassland, desert.

An assertion is incorrect because formal fallacies have a defect because of the poor form of the argument.
The informal fallacy has a defect in the content of the arguments.
So, Assertion is incorrect and Reason is correct. 
So, option B is the correct answer.

Let the number be 3x and 7x.
(3x+9):(7x+9) = 9:17, or
17(3x+9) = 9(7x+9), or
51x+153 = 63x+81, or
x = 6
Therefore the numbers are :-
First number = 3x = 3*6 = 18
Second number = 7x = 7*6 = 42
So, the correct option is (D)

Density = Mass/Volume
For rice, volume = (1000/1.13) + (1000/0.56) = 2670 cm³
For wheat, volume = (1000/1.39) + (1000/0.80) = 1969 cm³
For millet, volume = (1000/1.27) + (1000/0.77) = 2086 cm³
For maize, volume = (1000/0.97) + (1000/0.68) = 2510 cm³
∴ Rice have largest volume.

Number of ways of going from Chennai to Mumbai = 6
Number of ways of going from Mumbai to Goa = 4
∴ The number of ways of going from Chennai to Goa 
= 6 × 4
= 24 ways.

Let present age of father be 'x' years and present age of son be 'y' years.
At present, x = y²...(i)
After 6 years, (x + 6) = 7/2(y + 6)
⇒ 2(x + 6) = 7(y + 6)
⇒ 2x + 12 = 7y + 42
⇒ 2x = 7y + 30
⇒ 2y² = 7y + 30 [Using (i)]
⇒ 2y² - 7y - 30 = 0
⇒ y = 6, −(5/2)
∴ Present age of son = 6 years [∵ age cannot be negative]
∴ Present age of father = 6² = 36 years

Given,
A₀A₁ = 1 cm, A₁A₂ = 1 cm
Let's Consider the Triangle A₀A₁A₂ 
As this is a right angled triangle to get A₀A₂ = √ (1² + 1² ) = √2
Coming to Triangle A₀A₂A₃ 
As this is a right angled triangle to get A ₀A₃ = √(A₀A2² + A₂A₃²) = √ (√2² + 1² ) = √3
Simillarly for distance A₀A₄ = √(A₀A3² + A₃A₄²) = √ (√3² + 1² ) = √4
On Continuing we get A₀A₂₄ = √24 
A₀A₂₅ = √ (A₀A₂₄² + A₂₄A₂₅²) = √ (√24² + 1²) = √25 = 5

Let number of :
red cars = x
green car = y
red bike = z
green bike = w
According to the questions, x + y + z + w = 150...(i)
x + z = 60...(ii)
x + y = 100...(iii)
and, w = 20...(iv)
∴ (i) ⇒ 100 + z + 20 = 150 [Using (iii) and (iv)]
⇒ z = 30
Putting value of z in (ii) 
⇒ x + 30 = 60
⇒ x = 30
∴ Number of red cars = 30

From 1 am ,in every 12 hours the minute hand and the hour hand are exactly above each other 11 times.
⇒ In 24 hours they are exactly above each other 22 times
∴ From 1 am of a day to 1 am on the next day the minute hand and the hour hand are exactly above each other 22 times.

In square D, there are 2 circle of diameter 0.5, 4 circles of diameter 0.25 and 16 circles of diameter 0.125
∴ Shaded area of C

Shaded area of D

= π/4
Ratio of shaded area = 
∴ The ratio of shaded area in C and D would be 1.
If any square plane is covered by a single circle or by n different circles, in both cases the shaded area will be same.

Let number of students = s
and, number of teachers = t
Initially, each person is given the same number of chocolates as the number of students
⇒ Number of chocolates per person = s
⇒ Total number of chocolates = s(t + s) = ts + s²
Now, when 4 more students, total number of chocolates (considering same number of chocolates as earlier)
= s(t + s + 4)
= st + s² + 4s
According to the question; st + s² + 4s = ts + s² + 28
⇒ 4s = 28
⇒ s = 7
∴ Number of students now = 7 + 4 = 11 students

The reaction is CH₄+ 2O₂ → CO₂+ 2H₂O. O₂supplied = 1000*21/100 = 210 moles, N₂supplied = 1000*79/100 = 790 moles, ⇒ O₂unreacted = 210 – 100 = 110 moles, CO₂formed = 50 moles, H₂O formed = 100 moles. ⇒ Percentage of N₂ = 790/1050*100 = 75.2%.

Change in phase is an irreversible process.

The rate constant of reaction does not depend on concentration of reactant & product (only on nature of reactant & product).

CH₃CHFCHFCH(CH₃)₂ contains 2 chiral atoms. So, the number of possible stereoisomers is 4 (2²).

The enthalpy change of a reaction is the overall change in enthalpy as a reaction proceeds, taking into account the energy consumed by bond cleavage and the energy liberated by bond formation. The increase in disorder of the system is represented by its entropy, not its enthalpy.

The reaction is CH₄+ 2O₂ → CO₂+ 2H₂O. O₂supplied = 1000*21/100 = 210 moles, N₂supplied = 1000*79/100 = 790 moles, => Osub>2 unreacted = 210 – 100 = 110 moles, COsub>2 formed = 50 moles, Hsub>2O formed = 100 moles. ⇒ Percentage of H₂O = 100/1050*100 = 9.5%

In the reaction, Acetone reacts with HCN to form a cyanohydrin, dissociated proton from HCN activates the carbonyl, which facilitates the nucleophilic attack of CN.

Let the amount of nitrogen added be x, and amount of 20% nitrogen solution be P. Nitrogen balance: x + 0.2(P) = 0.4(100), Water balance: 0.8(P) = 0.6(100), ⇒ P = 75 Kg, ⇒ x = 0.4(100) – 0.2(75), ⇒ x = 25 Kg.

A nucleophile is a chemical species that donates an electron pair to an electrophile to form a chemical bond in relation to a reaction, it is an electron rich species.

Not all stereoisomers are diastereomers. For example, a pair of molecules which are non-superimposable mirror images of one another are enantiomers, not diastereomers.

Moles of bone dry air = 5, moles of H₂O produced = 6, ⇒ humidity = 6/5*100 = 120%.

The rate of reaction that does not involve gases does not depend on pressure.

For ideal gas PV = nRT, ⇒ P = 1*0.0821*300/1 = 24.63 atm.

There are several isomers of hexene, depending on the position and geometry of the double bond in the chain. One of the most common industrially useful isomers is 1-hexene an alpha-olefin.

Percentage of O₂ = 15/(10 + 10)*100 = 75%