How much base is needed to neutralize an acid

What semimetal can form four single covalent bonds.

If the root word engage means “to connect with something,” what does the word disengage mean in the following sentence? he disengaged the gears by stepping on the clutch pedal.a.added more engine powerb.activated a connection to the pedalc.stalled the engined.released a connection to the pedal

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.