(2.) A lab assistant Alex test for the presence of X, the balanced chemical equation is CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O. (3.) Another lab assistant perform the test, the balanced chemical equation is CaCO₃ + 2NaOH → Ca(OH)₂ + Na₂CO₃. (4.) The Substance X is Calcium carbonate.
The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
(2.) To test for the presence of substance X, a lab assistant, Alex, treats a sample of the material with hydrochloric acid. Bubbles of carbon dioxide gas are observed and collected during the test reaction.
The balanced chemical equation is
CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
(3.) Another lab assistant, Jess, disagrees with Alex, and treats a sample of substance X with sodium hydroxide. One of the products of this reaction is a compound called milk of lime (found to be only slightly soluble in water).
The balanced chemical equation is
CaCO₃ + 2NaOH Ca(OH)₂ + Na₂CO₃
The type of reaction is Double displacement reaction
(4.) The lab assistant Alex perform the valid test for substance X because it gives effervescence of bubbles. The substance X is calcium carbonate. When calcium carbonate react with dilute HCl then carbon dioxide gas bubbles is present in it.
Thus from the above conclusion we can say that (2.) A lab assistant Alex test for the presence of X, the balanced chemical equation is CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O. (3.) Another lab assistant perform the test, the balanced chemical equation is CaCO₃ + 2NaOH → Ca(OH)₂ + Na₂CO₃. (4.) The Substance X is Calcium carbonate.
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