Here we have to identify the metal powder by the given disposal.
The identification of Zinc can be done by 1 m nitric acid (HNO₃) and Ni(NO₃)₂ which will produce hydrogen gas by reaction and displacement reaction as shown below.
Zn + 2 HNO₃ = Zn(NO₃)₂ + H₂ (g)
Zn + Ni(NO₃)₂ = Zn(NO₃)₂ + Ni
The identification of lead can be done by the reaction with 1 m nitric acid (HNO₃) which produces lead nitrate.
The reaction is-
Pb + 4HNO₃ = Pb(NO₃)₂ + 2NO₂ + 2H₂O
The identification of platinum can be done by the reaction with all the given disposal as it will not react with any of the compound.
1. Identification of Zinc (Zn):
(a) Zn metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than zinc.
Zn + NaNO₃ = No reaction
(b) Zn metal will react with 1 m HNO₃ to form hydrogen gas. The reaction is:
Zn + 2 HNO₃ = Zn(NO₃)₂ + H₂ (g)
(c) Zn will react with nickel nitrate [Ni(NO₃)₂] because it may only cause displacement reaction the reduction potential of Zn²⁺/Zn (-0.76) is less than that of Ni²⁺/Ni (-0.23). Thus the reaction will be:
Zn + Ni(NO₃)₂ = Zn(NO₃)₂ + Ni
2. Identification of lead (Pb):
(a) Pb metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than Pb.
Pb + NaNO₃ = No reaction
(b) Pb reacts with HNO₃ to form lead nitrate. The reaction is:
Pb + 4HNO₃ = Pb(NO₃)₂ + 2NO₂ + 2H₂O
(c) The standard reduction potential of Pb²⁺/Pb is more than nickel Ni²⁺/Ni thus there will be no reaction between Pb and NI(NO₃)₂.
Pb + Ni(NO₃)₂ = No reaction.
3. Identification of platinum (Pt)
(a) Pt metal will not react with sodium nitrate (NaNO₃) as sodium remains at the lower position of the activity series than Pt.
Pt + NaNO₃ = No reaction.
(b) The standard reduction potential of Pt²⁺/Pt is so high (+1.188) thus there will be no reaction with HNO₃.
Pt + HNO₃ = No reaction
(c) The standard reduction potential of Pt²⁺/Pt is more than nickel Ni²⁺/Ni thus there will be no reaction between Pt and Ni(NO₃)₂.
Pt + Ni(NO₃)₂ = No reaction.
