Labour leader Johann Lamont said the people deserved to know which of the range of currency options the First Minister backed in the event of being denied his favoured formal currency union with the rest of the UK.
Conservative leader Ruth Davidson told Mr Salmond that keeping the pound within a formal union was "not in his gift" while Liberal Democrat leader Willie Rennie said he was not being fair to the people of Scotland.
The unionist parties at Westminster have already ruled out the option of a formal currency union.
But Mr Salmond insisted: "It is our pound and we're keeping it".
The heated exchanges at First Minister's Questions at Holyrood follow Tuesday's television debate on the referendum, during which Better Together leader Alistair Darling challenged Mr Salmond on the currency issue.
Ms Lamont said: "In the increasingly unlikely event that Scotland votes Yes, and in the likely event that the First Minister is unable to agree a currency union with the rest of the United Kingdom, can the First Minister tell the people of Scotland, what is Plan B?"
Mr Salmond replied: "The reason we are keeping the pound in a currency union, and the reason we are so unambiguous about it, is because we are appealing to the greatest authority of all, that is the sovereign will of the people of Scotland.
"After a Yes vote in the referendum, I am sure that Johann Lamont will be among those who accept that sovereign will of the people of Scotland.
"It is Scotland's pound. It doesn't belong to George Osborne, it doesn't belong to Ed Balls. It's Scotland's pound and we are keeping it."
Ms Lamont continued: "The First Minister has said on many occasions that he has a Plan B, C, D, E and F if there isn't a currency union.
"It is clear then that he has at least entertained the possibility that the currency union might not happen, so he claims to have a range of other options.
"Please share with us, what is Plan B?"
Mr Salmond said alternatives were outlined in the Scottish Government's white paper on independence.
He added: "These are the euro, which we don't support, a fixed or flexible exchange rate policy - perfectly viable but not as good as keeping Sterling.
"It also points out we cannot be stopped from keeping the pound because it's an international tradeable currency.
"Will she (Johann Lamont) not accept that the reason the white paper puts forward the view of keeping Sterling in a formal currency union is that it is best for Scotland, it is best for the United Kingdom?"
The Labour leader countered that the Prime Minister of the rest of the UK would have a "sovereign mandate" to say no to a formal currency union.
"It is not for the First Minister, no matter how limitless he thinks his powers are, to determine what is in the national interest of another country," she said.
Mr Salmond said there were three reasons why Mr Osborne, Mr Balls and the Prime Minister David Cameron were insisting there would be no currency union, but would change their position after a Yes vote.
He said: "Firstly there is the sovereign will of the Scottish people...secondly this plan is in the best interests of Scotland and it is also in the best interests of the rest of the UK...and thirdly, of course, Osborne, Balls and the Prime Minister are not saying they could stop us using the pound, they are saying that they want to keep for themselves the asset of the Bank of England."
Mr Salmond continued: "If you keep all of the assets of the United Kingdom, you end up with all of the liabilities of the United Kingdom, which after the work of George Osborne and Alistair Darling amounts to £1.3 trillion of debt."
Ms Lamont said it was "increasingly clear" Mr Salmond does not have a plan for Scotland.
She said: "Don't the people of Scotland deserve to know which (currency plan) it will be? And, if he doesn't tell us, isn't it clear that while he may have a plan to break up the United Kingdom, he doesn't have a plan for Scotland or the future of families across this country?"
Mr Salmond later suggested that the UK parties' pointed refusal to share the pound would go the same way as Scottish Conservative leader Ruth Davidson's "line in the sand" on devolution.
Ms Davidson campaigned to become Tory leader on a platform of offering no more devolution to Scotland, only to go on to offer what many regarded as the most comprehensive set of powers of all the parties if Scotland votes No.
He also welcomed comments by her deputy Jackson Carlaw that he would "man the barricades" for a currency union if Scotland votes Yes.
Mr Salmond insisted he would be there on the barricades with Mr Carlaw and was willing to withhold Scotland's share of the UK debt if its government refuses to share the pound.
"What is said after the referendum is different from what is said now," he said.
"I accept that, apparently, George Osborne and the Prime Minister have drawn a line in the sand on this matter.
"But as Ruth Davidson well knows, lines in the sand have a habit of being washed away.
"Therefore, I welcomed Ruth Davidson's revelation on June 15 in the Sunday Post that she will back a currency union in the event of a Yes vote, if that is what is best for Scotland."
He added: "Mind you, there's less enthusiasm than there was from deputy leader Jackson Carlaw.
"On February 21, he said after a Yes vote he would 'man the barricades for the pound' after independence.
"Can I say to Ruth Davidson and to Jackson Carlaw, I'll be there on the barricades with the Conservative Party."
Ms Davidson rejected the First Minister's interpretation, insisting she meant a continuing monetary union was "the best option for Scotland" as long as it remains in the United Kingdom.
"The vast majority of the people of England and Wales said in June it is not in their interests," she said.
"The First Minister of Wales said it is not in their interests. The permanent secretary to the Treasury has said it is not in England, Wales or Northern Ireland's interests.
"The Chancellor, the Shadow Chancellor, the Chief Secretary to the Treasury, have said it is not in their interests.
"The markets have said it is not in their interests."
She said a currency union is not in Mr Salmond's gift "and all the wishing in the world won't make it so".
Liberal Democrat leader Willie Rennie said the First Minister is "not being fair to the people of Scotland".
"He says he's got a currency plan and yet the First Minister can't even bring himself to describe the consequences," he said.
"The First Minister often refers to the Fiscal Commission, but I suspect most people don't have a copy of the Fiscal Commission paper at home.
"People don't know what they are recommending. They don't knock on the doors, the First Minister does.
"They're supposed to be his ideas. What are they and why can't he bring himself to give us a description of the consequences of his alternative?"
Mr Salmond said: "I'm glad Willie Rennie mentioned the Fiscal Commission, of course two Nobel Laureates and highly-distinguished economists."
He added: "In terms of consequences of other currency options, Professor David Bell has pointed out that 'it is the UK debt, not Scottish debt, and the UK has agreed it will pay back the debt'.
"You see, it might be extremely attractive for Scotland to be in a position where the UK seized the financial assets but weren't prepared to accept that they have the liabilities as well.
"It would be extremely attractive for Scotland to be debt-free. We would be in balance of payments and budget surplus, but it's not a reasonable position to put forward, which is why in the White Paper we are offering to pay our fair share of the massive liabilities built up by the likes of George Osborne.
"But that is dependent, of course, on having a fair share of the assets as well."