Question

question 12
1 pts
which reaction is not an example of a redox reaction?
ch₄ (g) + 2 o₂ (g) → co₂ (g) + 2 h₂o (g)
6 hcl (aq) + 2 al (s) → 2 alcl₃ (aq) + 3 h₂ (g)
2 (nh₄)₃po₄ (aq) + 3 ba(no₃)₂ (aq) → ba₃(po₄)₂ (s) + 6 nh₄no₃ (aq)
2 hg (l) + o₂ (g) → 2 hgo (s)
2 al₂o₃ (s) → 4 al (s) + 3 o₂ (g)
question 13
1 pts
which reaction is an example of an acid - base reaction?
2 hg(l) + o₂(g) → 2 hgo(s)
h₂co₃ (aq) → h₂o(l) + co₂ (g)
h₂so₄ (aq) + ca(oh)₂ (aq) → caso₄ (aq) + 2 h₂o(l)
fecl₃ (aq) + 3 koh(aq) → fe(oh)₃ (s) + 3 kcl(aq)
6 hcl(aq) + 2 al(s) → 2 alcl₃ (aq) + 3 h₂ (g)

Explanation:

Question 12

A redox reaction involves a transfer of electrons (change in oxidation states).

• For \(CH_4(g)+2O_2(g)\to CO_2(g) + 2H_2O(g)\): \(C\) in \(CH_4\) (\(C=- 4\)) changes to \(C = +4\) in \(CO_2\), \(O\) in \(O_2\) (\(O = 0\)) changes to \(O=-2\) in \(H_2O\) and \(CO_2\).
• For \(6HCl(aq)+2Al(s)\to2AlCl_3(aq)+3H_2(g)\): \(Al\) (\(Al = 0\)) changes to \(Al^{3+}\) (\(Al=+3\)), \(H\) in \(HCl\) (\(H = + 1\)) changes to \(H = 0\) in \(H_2\).
• For \(2(NH_4)_3PO_4(aq)+3Ba(NO_3)_2(aq)\to Ba_3(PO_4)_2(s)+6NH_4NO_3(aq)\): This is a double - displacement reaction. Oxidation states of \(N\), \(H\), \(P\), \(O\), \(Ba\) do not change.
• For \(2Hg(l)+O_2(g)\to2HgO(s)\): \(Hg\) (\(Hg = 0\)) changes to \(Hg^{2+}\) (\(Hg=+2\)), \(O\) (\(O = 0\)) changes to \(O=-2\).
• For \(2Al_2O_3(s)\to4Al(s)+3O_2(g)\): \(Al\) (\(Al = +3\)) changes to \(Al = 0\), \(O\) (\(O=-2\)) changes to \(O = 0\).

An acid - base reaction (neutralization) produces salt and water.

• For \(2Hg(l)+O_2(g)\to2HgO(s)\): This is a redox reaction (change in oxidation states: \(Hg:0\to + 2\), \(O:0\to-2\)).
• For \(H_2CO_3(aq)\to H_2O(l)+CO_2(g)\): This is a decomposition reaction.
• For \(H_2SO_4(aq)+Ca(OH)_2(aq)\to CaSO_4(aq)+2H_2O(l)\): \(H_2SO_4\) (acid) reacts with \(Ca(OH)_2\) (base) to form \(CaSO_4\) (salt) and \(H_2O\).
• For \(FeCl_3(aq)+3KOH(aq)\to Fe(OH)_3(s)+3KCl(aq)\): This is a double - displacement reaction (precipitation).
• For \(6HCl(aq)+2Al(s)\to2AlCl_3(aq)+3H_2(g)\): This is a redox reaction (\(Al:0\to+3\), \(H:+1\to0\)).

Answer:

\(2(NH_4)_3PO_4(aq)+3Ba(NO_3)_2(aq)\to Ba_3(PO_4)_2(s)+6NH_4NO_3(aq)\)

Question 13