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Railway RRB / NTPC

Railway RRB & NTPC MCQ questions — GK, Math, Reasoning, General Science.

903 Q 4 Subjects 10th / Graduate
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Difficulty: All Easy Medium Hard 901–903 of 903
Subjects in Railway RRB / NTPC
Q.901 Medium General Science Physics
The escape velocity from the surface of a planet depends on which two fundamental properties of that planet?
A Radius and temperature
B Mass and radius
C Density and temperature
D Atmospheric pressure and mass
Correct Answer:  B. Mass and radius
EXPLANATION

Escape velocity is mathematically derived as v = √(2GM/R), where G is gravitational constant, M is the planet's mass, and R is its radius.

These two properties directly determine the gravitational field strength at the planet's surface, which defines the minimum velocity needed to escape gravitational attraction.

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Q.902 Medium General Science Chemistry
What is the hybridization state of the central carbon atom in the carbonate ion (CO₃²⁻)?
A sp
B sp²
C sp³
D sp³d
Correct Answer:  B. sp²
EXPLANATION

In the carbonate ion CO₃²⁻, the central carbon atom forms three sigma bonds with oxygen atoms and is involved in resonance structures with delocalized pi electrons.

This trigonal planar geometry requires sp² hybridization, with three hybrid orbitals arranged at 120° angles and one unhybridized p orbital for pi bonding.

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Q.903 Medium General Science Chemistry
In the reaction between potassium permanganate and oxalic acid in acidic medium, what is the ratio of KMnO₄ to H₂C₂O₄ in the balanced equation?
A 1:2
B 2:5
C 3:5
D 5:2
Correct Answer:  B. 2:5
EXPLANATION

The balanced equation for this redox reaction in acidic medium is: 2KMnO₄ + 5H₂C₂O₄ + 3H₂SO₄ → K₂SO₄ + 2MnSO₄ + 10CO₂ + 8H₂O.

Potassium permanganate acts as an oxidizing agent (Mn⁷⁺ → Mn²⁺), while oxalic acid is oxidized (C²⁺ → C⁴⁺), giving the 2:5 molar ratio.

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