MCQOPTIONS
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				| 1. | 
                                    Chemical method of strengthening porcelain involves_________________? | 
                            
| A. | Exchange of aluminium and sodium ions | 
| B. | Exchange of aluminium and potassium ions | 
| C. | Exchange of sodium and potassium ions | 
| D. | None of the above | 
| Answer» D. None of the above | |