Class 11th

The set in which compounds have different nature is:

The metal that can be purified economically by fractional distillation method is:

Green chemistry in day-to day life is in the use of:

A s-block element (M) reacts with oxygen to form an oxide of the formula MO₂. The oxide is pale yellow in colour and paramagnetic. The element (M) is:

Among the given species the Resonance stabilized carbocations are:

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: The dihedral angles in H₂O₂ in gaseous phase is 90.2° and in solid phase is 111.5°

Reason R: The  change in dihedral angle in solid and gaseous phase is due to the difference in the intermolecular forces.

Choose the most appropriate answer from the options given below for A and R.

Outermost electronic configuration of a group 13 element, E, is 4s², 4p¹. The electronic configuration of an element of p-block period-five placed diagonally to element, E is:

A person whose mass is   100kg travels from Earth to Mars in a spaceship. Neglect all other object in sky and take acceleration due to gravity on the surface of the Earth and mars as 10 m/s² and 4m/s² respectively. Identify from the below figures, the curve that fits best for the weight of the passenger as a function of time.

A sheet block of 10kg rests on a horizontal floor as shown. When three iron cylinders are placed on it as shown, the block and cylinders go down with an acceleration 0.2 m/s². The normal reaction R' by the floor if mass of the iron cylinders are equal and of 20kg each, is_________N.

[Take g = 10 m/s² and ${\mu }_s=0.2]$  

A body of mass 'm' is launched up on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of friction between the body and plane is $\frac{\sqrt[]{x}}{5}$  if the time of ascent is half of the time of descent. The value of x is__________.