If electron have negative charge then why it don't attract positive charge protons in the nucleus if we know that positive and negative charge attract each other? ​

All atoms have the same number of electrons as protons, so the positive and negative charges "cancel out", making atoms electrically neutral. ... Because opposite electric charges attract each other, negative electrons are attracted to the positive nucleus.

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.