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Consider the reaction N2+ 3H2 → 2NH3 carried out at constant temperature and pressure. If ΔH and ΔE are the enthalpy and internal energy changes for the reaction, which of the following expression is true?
In the electrolytic method of obtaining aluminium from purified bauxite, cryolite is added to the charge in order to
In the electrolytic method of obtaining aluminium from purified bauxite, cryolite is added to the charge because it reduces the melting point of Bauxite (from 1200oC to 800o−900oC) and also it increases the electrical conductivity of the mixture.
Hence the correct option is (B).
By which of the following reagents, butanoic acid can be converted into butane?
Butanoic acid can be converted to butane by heating with hydriodic acid (HI) and red phosphorus (Red P).
Hence, the correct option is (A)
The X- coordinates of the particles of a system of bodies whose centre of mass is at origin will be?
If the centre of mass is at the origin, this means that some particles will be towards the left of the centre of mass and some towards the right of the centre of mass.
The particles towards the left of centre of mass will have a negative value of X-coordinate whereas those towards the right will have a positive value of X-coordinate.
In this case, the particles can not have always positive values of X-coordinates or always negative values of X-coordinates separately because the particles are uniformly distributed about the centre of mass of the body.
Hence, the correct option is (C).
Figure shows three resistor configurations R1,R2 and R3 connected to 3 V battery. If the power dissipated by the configuration R1,R2 and R3 is P1,P2 and P3 respectively then:
A junction diode has a resistance of 25 when forward-biased and 2500 when reverse-biased. The current in the arrangement shown in the figure will be
The junction diode is forward biased.
Therefore, the effective resistance
Which among the following is not an exact differential?
Heat ′Q′ is a path-dependent function, hence its exact differentiation is not possible, however, internal energy, entropy, and Gibbs free energy are state functions, hence can be differentiated exactly.
Hence, the correct option is (A).
A resonance air column of length 40 cm resonates with a tuning fork of frequency 450 Hz. Ignoring end corrections, the velocity of sound in air will be:
We know that the minimum length of the air column tube corresponds to the fundamental mode of vibrations. Hence, by ignoring end corrections-
Length of column = 40 cm
= 0.4 m
Frequency of tuning fork = 450 m
Using the formula, n = v/4I
V = 450 × 4 × 0.4
=720 m/s
Hence,the correct option is (D).
A rocket is fired from Earth to the Moon. The distance between Earth and the Moon is and the mass of Earth is 81 times the mass of the Moon. The gravitational force on the rocket will be zero when its distance from the Moon is:
The net force on the rocket is zero.
Because force due to the earth and force due to the moon is the same but in opposite direction.
The displacement of electrons in multiple bonds in the presence of attacking reagent is called:
The electromeric effect is a temporary effect brought into play at the requirement of attacking reagent. The electromeric effect refers to a molecular polarizability effect occurring by an intramolecular electron displacement. It is a temporary effect.
Hence, the correct option is (B).
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