Class 12th

Which one of the following is not formed where acetone reacts with 2-pentanone in the presence of dilute NaOH followed by heating?

Polar molecules are the molecules:

For a plane electromagnetic wave propagating in $\mathrm{x}$ -direction, which one of the following combination gives the correct possible directions for electric field (E) and magnetic field (B) respectively?

At 298 K, the standard electrode potentials of Cu²⁺/Cu, Zn²⁺ /Zn, Fe²⁺ /Fe and Ag⁺ /Ag are 0.34 V, -0.76 V, -0.44 V and 0.80 V, respectively. On the basis of standard electrode potential, predict which of the following reaction can not occur?

Which statement regarding polymers is not correct?

Given below are two statements : One is labelled as

Assertion (A) and the other is labelled as Reason (R).

Assertion (A): The stretching of a spring is determined by the shear modulus of the material of the spring.

Reason (R): A coil spring of copper has more tensile strength than a steel spring of same dimensions.

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

In a potentiometer circuit a cell of EMF $1.5\mathrm{V}$ gives balance point at $36\mathrm{c}\mathrm{m}$  length of wire. If another cel) of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?

RMgX + CO₂ --(dry ether)--> Y --(H₃O⁺)--> RCOOH

What is Y in the above reaction?

The given graph is a representation of kinetics of a reaction.

The y and x axes respectively are for zero and first order reactions, respectively are:

A ball is projected with a velocity, $10{\mathrm{m}\mathrm{s}}^{-1}$ , at an angle of ${60}^{?}$  with the vertical direction, its speed at the highest pint of its trajectory will be :