The number of correct statements is/are 
1) All 15 group elements exhibit allotropy except nitrogen
2) Nitrogen has inability to form pπ- pπ multiple bonds with itself and with other elements having small size and high eletronegativity atom
3) N-N Single bond is weaker than p-p single bond because of high intereletronic repulsion of the non-bonding electrons, owing the small bond length
4) Nitrogen has greater catenation than phosphorous.
5) Moist $S{O}_2$ behaves as a oxidizing agent 
6) Electron gain enthalpy order is $Cl>Br>F>I$  
7) Phosphonic acid has two reducing hydrogen atoms 
8) The ${\left[Fe{\left(H_{2}O\right)}_{5}NO\right]}^{+2}$ test for nitrates depends on the ability of $F{e}^{+2}$ to oxidise nitrate to nitric oxide