which of the following occurs when a sample of 0.1M HNO3 is tested?

a) phenolphthalein turns pink
b) bromthymol blue turns yellow
c) Ca9s) reacts and produces CO2 (g)
d) Na (s) reacts and rpoduces NO2 (g)

3 answers

I believe bromthymol blue will turn yellow with HNO2. I can't read c. Both a and d are false.
c) Ca (s) reacts and produces Co2(g)

Can you explain to me why it's b please?
Nevermind, I think I understand it now.
Thanks.