The former chancellor and head of the pro-UK Better Together campaign told an audience of business leaders in Edinburgh that the Scottish Government was refusing to address basic questions about the country's future.
He said: "At the time the row began over Scotland's place in the EU began, I said this was an issue that was of paramount importance to the debate on our country's future and to the lives of the people who live and work here.
"We simply cannot allow basic questions to go unanswered. We cannot have people being asked to vote in the referendum unless they know what they are voting for.
"Alex Salmond would be much better served just coming clean and saying what we all know to be the case. Scotland may well be a member of the EU if it goes it alone, but it will not be done on the basis of a nod and a wink. There would have to be negotiations. He is a politician. He should know how political organisations work.
"Alex Salmond cannot be a politician who is oblivious to politics. The gamble he is proposing has nothing to do with the racetrack and everything to do with the future of our country."
The SNP Government has claimed that an independent Scotland would continue in EU membership on the same terms as the UK, including its opt-out from the euro single currency.
The position has been challenged by leading academics Graham Avery and Neil Walker, who have said that while Scots would remain European citizens, EU entry talks would include discussion of the euro.
l Scotland's top law officer has defended the Scottish Government from accusations that ministers could have admitted months ago that no specific legal advice existed on Scotland's place in the EU after independence.
Lord Advocate Frank Mulholland told MSPs that "it's for ministers to judge the appropriate point to seek specific legal advice from law officers".