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.
Not the product of a single batch or a single barrel, but a single distillery. The root of all confusion lies in the simple word single. A single-malt scotch whisky is nothing more or less than the product of a single distillery. Not the product of a single batch or a single barrel, but a single distillery. A single-malt Lagavulin may contain whiskies from many barrels produced at the Lagavulin distillery, but it will contain only whiskies produced at Lagavulin.