A. Depending on your investment style and time horizon, this usually is not a good idea for most people.
First, you’ll owe interest on the loan, so your investment is not free of cost.
Second, there’s no assurance you’ll earn a profit with your investments. Just recall what happened in 2008, when the stock market fell over 30%, and millions of people subsequently got their homes foreclosed.
If your purpose is to create some liquidity, you can open a home equity line of credit. If you don't use it, there will be no cost to you.