I have to figure out which elements to use that would result in the following re

Question

I have to figure out which elements to use that would result in the following reaction: You watch this science geek showing off some science magic to some kids. The scientist pours ____ g of white solid (A) into ___ ml of water in a ___ ml flask. The solid disappears and the water turns pink. Then the chemist pours ___ ml of a colorless liquid (B) into the flask, puts a rubber stopper on the flask, and shakes the flask for a few seconds. The stopper flies through the air. The solution stays pink. Then, the person adds ___ ml of a second colorless liquid (C) to the flask. A white solid forms and the pink solution turns colorless.

Options for the elements are: 1 M HCl (50 ml per group), vinegar (50 ml per group), NaOH or KOH pellets, Phenolphthalein, NaCl solid, Mg(NO3)2 or MgCl2 solid, Mg(OH)2 solid, Ca(NO3)2 or CaCl2 solid, Na2CO3 solid, magnesium metal, Baking soda (NaHCO3), iron metal, Tums tablet (CaCO3), ethanol.

Thanks in advance!

Explanation / Answer

solution:

It is believed that you need help to fill in those blanks. You need information on compounds that cause this to happen from the given list.

1st blank - Na2CO3 (white solid) or NaHCO3

4th blank - HCl acid

The reaction between HCl and sodium carbonate or sodium bicarbonate is vigorous (exothermic), and it liberates CO2 that knocks off the stopper after rigorous shaking

5th blank - HCl is added more, then a precipitate of NaCl is formed which is white in colour.

Please see the attached reaction and its stoichiometry

Na2co3+2Hcl ----->2Nacl+Co2+H2o

NaHco3+Hcl------> Nacl+Co2+H20

Note that carbonates of sodium are more reactive than calcium.

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