If the temperature of a gas is increased from 27°C to 327°C at constant pressure, the volume becomes how many times the original? MCQ with Answer and Explanation

Explanation:
1/4 = (1/2)², so 2 half-lives = 40 days → half-life = 20 days. After 1 half-life 1/2 remains, after 2 half-lives 1/4.

Explanation:
A catalyst lowers the activation energy (Ea) by providing an alternative reaction mechanism, thereby increasing the rate of both forward and reverse reactions equally. It does not affect the equilibrium constant, enthalpy change (ΔH), or the position of equilibrium. It remains chemically unchanged after reaction. Positive catalysts speed up, negative catalysts slow down. Enzymes are biological catalysts.

Explanation:
Bohr's model successfully explains the spectrum of hydrogen and hydrogen-like species (single electron systems like He⁺, Li²⁺). However, it fails to explain the spectra of multi-electron atoms due to electron-electron repulsions and cannot account for the splitting of spectral lines in magnetic (Zeeman) and electric (Stark) fields.