NTA JEE Main 26th February 2021 Shift 2

The $$NaNO_3$$ weighed out to make 50 mL of an aqueous solution containing 70.0 mg Na$$^+$$ per mL is ______ g.
(Rounded off to the nearest integer) [Given: Atomic weight in g mol$$^{-1}$$ - Na: 23; N: 14; O: 16]

A ball weighing 10 g is moving with a velocity of 90 m s$$^{-1}$$. If the uncertainty in its velocity is 5%, then the uncertainty in its position is ______ $$\times 10^{-33}$$ m. (Rounded off to the nearest integer)
[Given: h = $$6.63 \times 10^{-34}$$ Js]

The average S - F bond energy in kJ mol$$^{-1}$$ of $$SF_6$$ is ______. (Rounded off to the nearest integer)
[Given: The values of standard enthalpy of formation of $$SF_6(g)$$, $$S(g)$$ and $$F(g)$$ are $$-1100$$, 275 and 80 kJ mol$$^{-1}$$ respectively.]

The pH of ammonium phosphate solution, if $$pK_a$$ of phosphoric acid and $$pK_b$$ of ammonium hydroxide are 5.23 and 4.75 respectively, is ______

In mildly alkaline medium, thiosulphate ion is oxidized by $$MnO_4^-$$ to 'A'. The oxidation state of sulphur in 'A' is ______

The number of octahedral voids per lattice site in a lattice is ______. (Rounded off to the nearest integer)

When 12.2 g of benzoic acid is dissolved in 100 g of water, the freezing point of solution was found to be $$-0.93$$ °C ($$K_f(H_2O) = 1.86$$ K kg mol$$^{-1}$$). The number (n) of benzoic acid molecules associated (assuming 100% association) is ______.

Emf of the following cell at 298 K in V is $$x \times 10^{-2}$$
$$Zn|Zn^{2+}(0.1M)||Ag^+(0.01M)|Ag$$
The value of $$x$$ is ______ (Rounded off to the nearest integer)
[Given: $$E^\theta_{Zn^{2+}/Zn} = -0.76$$ V; $$E^\theta_{Ag^+/Ag} = +0.80$$ V; $$\frac{2.303RT}{F} = 0.059$$]

If the activation energy of a reaction is 80.9 kJ mol$$^{-1}$$, the fraction of molecules at 700 K, having enough energy to react to form products is $$e^{-x}$$. The value of $$x$$ is (Rounded off to the nearest integer) [Use R = 8.31 J K$$^{-1}$$ mol$$^{-1}$$]

The number of stereo isomers possible for $$[Co(ox)_2(Br)(NH_3)]^{2-}$$ is ______.
[ox = oxalate]