19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
The structure would be best classified as a(n)
Acetals are
Formalin is an aqueous solution of :
A strong base can abstract an alpha-hydrogen from
The formula of chloral is (a)퐶퐻3퐶퐻= 푁퐻퐶6퐻5
Aldehydic group can occur :
The general formula of both aldehydes and ketones is:
The IUPAC name of CH3COCH(CH3)2 is :
[AMU 2009] The radius of the Bohr orbit of the H-atom is r. Then the radius of the first orbit of Li²⁺ will be
The e/m ratio for anode rays (positive rays) in comparison to cathode rays is:
The electrical discharge through gases could be observed only at
In the Rutherford scattering experiment, most α-particles passed straight through the gold foil because
Rutherford's nuclear model of the atom failed to explain
Calculate the frequency of yellow radiation having wavelength 5800 Å.
Which is NOT a characteristic of Planck's quantum theory of radiation?
The number of photons of light with wave number ν̄ = 2.5 × 10⁶ m⁻¹ necessary to provide 1 J of energy are
The number of photons emitted in 10 hours by a 60 W sodium lamp (λ = 6000 Å) is approximately
The energy required to break one mole of Cl–Cl bonds in Cl₂ is 242 kJ mol⁻¹. The largest wavelength of light capable of breaking a single Cl–Cl bond is
Ultraviolet light of 6.2 eV falls on an aluminium surface (work function = 4.2 eV). The kinetic energy (in joule) of the fastest electron emitted is approximately:
The threshold wavelength for the photoelectric effect on sodium is 5000 Å. Its work function is:
If the threshold frequency of a metal for the photoelectric effect is ν₀, which of the following will NOT happen?
The ionization energy of H atom is 13.6 eV. The ionization energy of Li²⁺ ion will be
Energy of electron of hydrogen atom in the second Bohr orbit is
For a Bohr atom, angular momentum of the electron is (n = 1, 2, 3 …)
The ratio of the energy difference between the 1st and 2nd Bohr orbits to that between the 2nd and 3rd Bohr orbits is