Question

questions

1. lets say that you have two bottles on the shelf. both labels have fallen off and you need to know which substance is nacl and which is the nai. you cannot taste the contents because that would just be stupid! and the contents have very little odor. how do you determine which is which? using a chemical test, how could you distinguish sodium chloride (table salt) from sodium iodide (a poison)? show the reaction.
2. how could you distinguish between solid barium chloride and solid barium sulfate?
3. washing soda na₂co₃ and baking soda, nahco₃ are chemically very similar substances. both compounds contain the same types of atoms. it is not a good idea to assume that you can substitute washing soda for baking soda. why?
4. we have seen that carbonates react with acids; would you expect na₂co₃ to react with hcl? write the chemical equation for the reaction (a double displacement reaction, switch the partners).

Explanation:

Step1: Identify a reagent for NaCl and NaI

Silver nitrate ($AgNO_3$) can be used. Chloride ions react with silver ions to form a white - precipitate, and iodide ions react with silver ions to form a yellow - precipitate.
$NaCl(aq)+AgNO_3(aq)
ightarrow AgCl(s)+NaNO_3(aq)$ (white precipitate)
$NaI(aq)+AgNO_3(aq)
ightarrow AgI(s)+NaNO_3(aq)$ (yellow precipitate)

Step2: Distinguish $BaCl_2$ and $BaSO_4$

Barium chloride ($BaCl_2$) is soluble in water while barium sulfate ($BaSO_4$) is insoluble in water. Add water to the two solids. If it dissolves, it is $BaCl_2$, if it does not dissolve, it is $BaSO_4$.

Step3: Explain the non - substitution of washing soda and baking soda

Washing soda ($Na_2CO_3$) is a stronger base than baking soda ($NaHCO_3$). In baking, baking soda decomposes upon heating to produce carbon dioxide gas which causes the dough or batter to rise. Washing soda does not have this property and its strong basicity can affect the taste and texture of baked goods.

Step4: Write the reaction equation of $Na_2CO_3$ and $HCl$

$Na_2CO_3(aq)+2HCl(aq)
ightarrow 2NaCl(aq)+H_2O(l)+CO_2(g)$

Answer:

1. Use silver nitrate solution. $NaCl(aq)+AgNO_3(aq)

ightarrow AgCl(s)+NaNO_3(aq)$ (white precipitate), $NaI(aq)+AgNO_3(aq)
ightarrow AgI(s)+NaNO_3(aq)$ (yellow precipitate).

1. Add water. The soluble one is $BaCl_2$, the insoluble one is $BaSO_4$.
2. Washing soda is a stronger base and does not decompose to produce gas in baking like baking soda, and its strong basicity can affect the taste and texture of baked goods.
3. $Na_2CO_3(aq)+2HCl(aq)

ightarrow 2NaCl(aq)+H_2O(l)+CO_2(g)$