Ninety kilograms of sodium nitrate is dissolved in 110 kg of water. When the dissolution is complete (at time ), pure water is fed to the tank at a constant rate , and solution is withdrawn from the...

Ninety kilograms of sodium nitrate is dissolved in 110 kg of water. When the dissolution is complete (at time ), pure water is fed to the tank at a constant rate , and solution is withdrawn from the tank at the same rate. The tank may be considered perfectly mixed.