JAMB - Chemistry (2007 - No. 42)
When temporary hard water is boiled for sometime in a kettle, the inner surface of the kettle becomes coated with a deposit of
calcium tetraoxosulphate(VI)
calcium trioxocarbonate (IV)
calcium hydrogentrioxocarbonate (IV)
aluminium trioxocarbonate (IV)
Forklaring
When temporary hard water is boiled for some time in a kettle, the inner surface of the kettle becomes coated with a deposit of Calcium trioxocarbonate(IV), CaCO\(_3\), which originated from Calcium hydrogen trioxocarbonate(IV), Ca(HCO\(_3\))\(_2\).
Ca(HCO\(_3\))\(_2\) → CaCO\(_3\) + H\(_2\)O + CO\(_2\)