Check the % concentration of sodium hypochlorite" on the dollar store bottle.
I was at Menards a week ago and my wife asked me to grab a bottle of bleach. They had (3) choices, Clorox (7.5%) and two Menards-branded. One was a little cheaper than the Clorox and was also 7.5% while the other was 1/2 the price of Clorox and nowhere on the bottle did it state the "bleach" concentration. Being a chemical like that, I was pretty surprised.
Pretty sure that’s a regulated amount…
I learned way more about it than I ever cared to know a few years back in my days in the Chemistry stockroom and troubleshooting an experiment where we used bleach as an oxidizing agent. We had stocked up on “Concentrated bleach” from one of the chemical suppliers(they gave us a deal, and at a university sometimes that’s just easier) and all of a sudden that experiment quit working unless we used some older plain “bleach” we had on hand.
I ended up doing a dive into the labeling and such, as well as buying a bottle of nearly every “bleach” Kroger sold.
What I found, and I’m working sort of from memory, is that “bleach”, no qualifiers, is 5% sodium hypochlorite, while “concentrated” is generally 6.5% and “ultra” is 7.5%.
BTW, I had a terrible time even finding just plain bleach. I ended up with the most generic looking bottle I could find, and was only able to get it in quart bottles.
Also, for this experiment, we never were able to get anywhere by diluting higher concentration bleach down to 5%. I suspect it goes back to how it is made, which is by dissolving chlorine gas in sodium hydroxide, and I expect that the higher ultimate concentration of sodium hypochlorite changes this. I did do some starch-iodine titrations to confirm bleach content, but never an acid-base titration to look at this part(and that can get tricky dealing with as much sodium hydroxide as is normally present in bleach anyway, plus acidifying in a titration releases chlorine…a common cheap way under other circumstances to make chlorine water…).