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 former is called base malt; the latter is known as specialty malts. The grain bill of a beer or whisky may vary widely in the number and proportion of ingredients. For example, in beer-making, a simple pale ale might contain a single malted grain, while a complex porter may contain a dozen or more ingredients.