Threshold frequency, ν0 is the minimum frequency which a photon must possess to eject an electron from a metal. It is different for different metals. When a photon of frequency 1.0*1015 s–1 was allowed to hit a metal surface, an electron having 1.988 * 10–19 J of kinetic energy was emitted. Calculate the threshold frequency of this metal. Show that an electron will not be emitted if a photon with a wavelength equal to 600 nm hits the metal surface.

Find out the number of following orders which are INCORRECT against the mentioned properties:

(i) Ortho hydrogen > Para hydrogen (Stability at low temperature)

(ii) Ethanol > Glycerol (Viscosity)

(iii) D₂ < He (Boiling point)

(iv) HF > H₂O (Melting point)

(v) H₃BO₃ > BF₃ (Melting point)

(vi) NH₃ < SbH₃ (Boiling point)

(vii) H₂O₂ > H₂O (Strength of hydrogen bond)

(viii) H₂O < D₂O (Freezing point)

(ix) $H{F}_2^{\Theta }$  < HF (Strength of hydrogen bond)

(x) D₂O < H₂O (Bond energy)

Consider the following reaction:
(A substituted phenol reacts with H? and CrO?Cl to produce product 'P'.)
The product ‘P’ gives positive acetyl chloride test. This is because of the presence of which of these –OH group(s)?
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The number of radial land angular nodes in 4d orbital are, respectively

The spin-only magnetic moment value of species is________× 10^-2 BM. (Nearest integer)

[Given: <!-- [if gte mso 9]><xml> </xml><![endif]-->  $\sqrt[]{3}=1.73]$

Which of the following relation is not correct?