Class 11th

For a photochemical reaction A → B, 1.0*10^-5 mole of B were formed on absorbing 1.2 * 10¹⁹ photons, quantum efficiency is : (NA = 6 * 10²³)

A man is walking on a straight line. The arithmetic mean of the reciprocals of the intercepts of the line on the coordinate axes is $\frac{1}{4}.$  Three stones A, B and C are placed at the point (1, 1), (2, 2) and (4, 4) respectively. Then which of these stones is / are on the path of the man?

Let a circle C touch the lines L₁ : 4x – 3y + K₁ = 0 and L₂ : 4x – 3y + K₂ = 0, K₁, K₂  $\in$  R. If a line passing through the centre of the circle C intersects L₁ at (-1,2) and L₂ at (3, -6), then the equation of the circle C is:

The equilibrium constant Kp for a homogenous gaseous reaction is 10^-3, the standard Gibb's free energy change (ΔG°) in cal mol^-1 for the reaction at 27°C (using R = 2 cal K^-1 mol^-1) is :

Two glass bulbs A and B are connected by a very small tube having a stop-cock. Bulb A has a volume of 100 cm³ and contained the gas; while bulb B was empty. On opening the stop-cock, the pressure fell down to 40%. The volume (in mL) of the bulb B must be :

A 500g tooth-paste sample has 0.2g fluoride concentration. What is the concentration of fluoride in terms of ppm level ?

The maximum number of electrons with n = 3 and l = 3 is:

ΔH_f° of CO₂(g), CO(g), N₂O(g) and NO₂(g) in kJ mol⁻¹ respectively is -393, -110, 81 and 34. Calculate the ΔH in kJ for the following reaction :
2NO₂(g) + 3CO(g) → N₂O(g) + 3CO₂(g).

The oxidation number of phosphorus in ATP (adenosine triphosphate) is :

One mole of water is converted to vapour at its boiling point which is 100°C and at 1 atm. For this process, which one of following statement is correct?