Nicola Sturgeon will tell an audience in Cardiff independence can create "a truly equal relationship across these islands".
The speech comes two years to the day that Scotland would become independent under the Government's timescale, if there is a Yes vote in September's referendum.
She will say: "The very foundation stone on which the No campaign bases its argument is in effect being demolished by the leaders of that campaign.
"Those opposed to independence claim that the UK, as it currently stands, is an equal partnership of nations and of people. But in its attempts to scare voters in Scotland, the No campaign is destroying the very idea that the UK is a partnership of equals.
"The leaders of the No campaign are going out of their way to demonstrate where they think power really lies - Westminster.
"In the event of independence we are told we have the obligation to pay a share of the debt run up by successive Westminster Chancellors. But we are also told we have no, or little, right to a share of the assets we have contributed to and helped pay for through our taxes, NI contributions and TV licences."
She will add: "Independence offers the greatest opportunity we will ever have to build a better Scotland and a truly equal relationship across these islands."