WAEC Chemistry 2010 Theory — Question 39

Model answer

I. Physical properties: Carbon (IV) oxide is gaseous at room temperature; it is denser than air. II. Chemical properties: it reacts with red hot carbon to give carbon monoxide, CO: CO2(g)+C(s)→2CO(g); it reacts with lime water to form calcium trioxocarbonate (IV) or calcium hydrogentrioxocarbonate (IV) if in excess: CO2(g)+Ca(OH)2(aq)→CaCO3(s)+H2O(l); 2CO2(g)+Ca(OH)2(aq)→Ca(HCO3)2(aq).