Which from following compounds does NOT contain nitrogen in it?

A container contains $4 \mathrm{~g} \mathrm{H}_2, 4 \mathrm{~g} \mathrm{He}$ and certain amount of 'Ne' at a certain temperature. What is the mass of 'Ne' required so that the partial pressure exerted by 'Ne' is equal to the partial pressure of He ?

Find the EAN of Zn in $\left[\mathrm{Zn}\left(\mathrm{NH}_3\right)_4\right]^{2+}$ ?

If standard reduction potential $\left(\mathrm{E}^{\circ}\right)$ of $\left(\mathrm{Mg}_{(\mathrm{aq})}^{+2} \mid \mathrm{Mg}_{(\mathrm{s})}\right),\left(\mathrm{Ag}_{(\mathrm{aq})}^{+} \mid \mathrm{Ag}_{(\mathrm{s})}\right),\left(\mathrm{Zn}^{+2}{ }_{(\mathrm{aq})} \mid \mathrm{Zn}_{(\mathrm{s})}\right)$ and $\left(\mathrm{Cu}^{+2}{ }_{(\text {aq })} \mid \mathrm{Cu}_{(\text {s })}\right)$ are $-2.37 \mathrm{~V},+0.79 \mathrm{~V},-0.76 \mathrm{~V}$ and +0.34 V respectively. Which of the following reaction is spontaneous?