## The value of Planck’s constant is 6.63 10-34 Js. The velocity of light is 3 x 108 ms-1. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of 6 x 10^15 s-1 ?

Solution A) 50 B) 75 C) 10 D) 25

## Calculate the energy in joule corresponding to light of wavelength 45 nm. (Planck’s constant, h = 6.63 x 10-34 J s, speed of light, c = 3 x 108 m s-1 )

(a) 6.67 x 1015 (b) 6.67 x 1011 (c) 4.42 x 10-15 (d) 4.42 x 10-18 Solution

## H 3 C − C H = C H 2 + H C l—————–> in the presence of peroxide the intermediate of reaction is

Ch3-c+h—-Ch3 Because peroxide will work in the presence of HBr not in the presence of HCl.

## For the reaction, C 2 H 5 O H + H X Z n X 2 ⟶ C 2 H 5 X , the order of reactivity is

Because the reaction follows SN1 mechanism and hence the halide formed is stable when it is of a larger size and size increases down the group. HI>HCL>HBr

## Which reaction is not a redox reaction

i) H2 + Cl2 ——> 2Hcl ii) BaCl2 + NaSo4——->BaSo4 +2NaCl iii) Zn + CuSo4——-> ZnSo4 + Cu Vi) 2Kclo3I2——->2KIO3 + Cl2 Answer BaCl2 + NaSo4——->BaSo4 +2NaCl Explanation H2 + Cl2 → 2HCl is an oxidation-reduction (redox) reaction. Oxidation: Hydrogen atoms in H2 lose electrons and become oxidized to H+ Reduction: Chlorine atoms in Cl2 … Read more

## As near midnight as ever, according to scientists, the Doomsday Clock will occur in 2024.

Doomsday clock 2024: According to experts projecting the planet’s future, there is a “continuing unprecedented level of risk.” Experts predicting the possibility of a worldwide catastrophe stated that the Doomsday Clock will linger at ninety seconds to midnight after war raged in the Middle East and Ukraine in 2023. The countdown, a metaphor for a … Read more