yes we have to limit our loss per trade as much as it's possible maintaining target risk-reward ratio, although too much losses becomes disturbing as you start to doubt that you trading system does have an edge
EURUSD is the most traded pair for scalping, however trading on this pair doesn't mean will always make a profit, high volatility without good patience waiting for best momentum may lead to failure.
In my experience, the best pairs for scalping are major pairs such as GBPUSD or EURUSD, the spreads are also tighter in EURUSD, which is an advantage for scalping traders.
True! Scalping is a double-edged sword. You can both win and lose a high amount of money in a short-period of time. You should have a strong trading psychology, discipline, and quick exit strategy to become a profitable scalper.