Class 11th

Copper reduces $N{O}_3^{-}$ into NO and NO₂ depending upon the concentration of HNO₃ in solution. (Assuming fixed $\left[C{u}^{2+}\right]and{P}_{NO}=P_{N{O}_2}$ ), the HNO₃ concentration at which the thermodynamic tendency for reduction of $N{O}_3^{-}into$ NO and NO₂by copper is same is 10^x M. The value of 2x is……. (rounded-off to the nearest integer).

$[Given,E_{C{u}^{2+}/Cu}^0=0.34V,E_{N{O}_3^{-}/NO}^0=0.96V,E_{N{O}_3^{-}/N{O}_2}^0=0.79Vandat298K,\frac{RT}{F}\left(2.303\right)=0.059]$

Complete combustion of 1.80g of an oxygen containing compound (C_x H_y O_z) gave 2.64g of CO₂ and 1.08g of H₂O. The percentage of oxygen in the organic compound is

Water does not produce CO on reacting with

Compound (s) which will liberate carbon dioxide with sodium bicarbonate solution is/are:

A small bob tied at one end of a thin string of length 1m is describing a vertical circle so that the maximum and minimum tension in the string are in the ratio 5 : 1. The velocity of the bob at the highest position is ……………… m/s. (Take g = 10 m/s²)

A mono-atomic gas of mass 4.0u is kept in an insulated container. Container is moving with velocity 30 m/s. If container is suddenly stopped then change in temperature of the gas (R = gas constant) is $\frac{x}{3R}.$  Value of x is…………….

Given below are two statements:

Statement I : The pH of rain water is normally $\sim 5.6$

Statement II : If the pH of rain water drops below 5.6, it is called acid rain.

In the light of the above statements, choose the correct answer from the options given below

The potential energy (U) of a diatomic molecule is a function dependent on r (interatomic distance) as $U=\frac{\alpha }{r^{10}}-\frac{\beta }{r^5}-3$

Where, and are positive constants. The equilibrium between two atoms will be ${\left(\frac{2\alpha }{\beta }\right)}^{\frac{a}{b}},$ ${\frac{}{}}^{\frac{}{}}$ where a =……………. 

Given below are two statements:                                        

Statement I : An allotrope of oxygen is an important intermediate in the formation of reducing smog.

Statement II : Gases such as oxides of nitrogen and sulphur present in troposphere contribute to the formation of photochemical smog.

In the light of the above statements, choose the correct answer from the options given below:

The same size images are formed by a convex lens by a convex lens when the object is placed at 20cm or at 10cm from the lens. The focal length of convex lens is ……………cm.