Consider the following reactions: (i) H(aq)++OH(aq)−→H2O(i),ΔH =−X1 kJ mol−1 (ii) H2(aq)+21O2(aq)→H2O(I)ΔH =−X2 kJ mol−1 (iii) CO2( g)+H2(g)→CO(g)+H2O,ΔH =−X3 kJ mol−1 (iv) C2H2(g)+25O2(g)→2CO2(g)+H2O(i), ΔH=+X4 kJ mol−1 Enthalpy of formation of H2O(l) is:
Held on 30 Apr 2007 · Verified 9 Jul 2026.
+X3 kJ mol−1
−X4 kJ mol−1
+X1 kJ mol−1
−X2 kJmol−1
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