In a large, heat-proof pitcher, combine the boiling water, baking soda & sugar mix well to dissolve the sugar. Add the tea bags and let steep for 10 minutes.
Remove the tea bags.
Add the lemon juice and fill the rest of the pitcher with cold water.
Refrigerate until chilled.
Add lemon slices and ice to glasses and pour the tea over the ice and lemon slices to serve.
Notes
The longer you steep the tea, the stronger the taste.