If the double bond is broken heterolytically, formal charge pairs result, as shown in the other two structures. The preferred charge distribution will have the positive charge on the less electronegative atom (carbon) and the negative charge on the more electronegative atom (oxygen).
Single malt Scotch. Single malt Scotch is single malt whisky made in Scotland. To be a single malt scotch the whisky must have been distilled at a single distillery using a pot still distillation process and made from a mash of malted grain. In Scotland, the only grain allowed to be used in a single malt whisky is barley.
The Difference Between Single- and Double-Malt Scotch. To understand the difference between a single-malt scotch and a double-malt scotch, some whiskey terms must be explained. However, the simple explanation is that a single-malt scotch comes from only one distillery and often refers to scotch that comes from one batch.