Question

Qual Analysis Qual-6 07/24/2018 Questions (attach extra shects if you need more space for your answers): 1. For Part 1, write the net ionic equations for any precipitates that formed or gases evolved For Part 2, write the net ionic equations for any precipitations that occurred. 2. 3. Give a simple test that would allow you to distinguish between the following pairs of anions. Tell what you would do and what you should observe for each anion. a. CO and SO CI' and SO b. c. CO and CI 4. Give a simple test that would allow you to distinguish between the following pairs of cations. Tell what you would do and what you should observe for each cation. a. B and Ca b. Ca and Sr c. Ca and NH 5. Write the symbol of the cation or anion that give(s) the following reaction: a. Forms a precipitate with AgNOs that does not dissolve in HNO3 b. Forms a gas (bubbles) with HCI but has no odor. c. Gives a bright, yellow-green flame test. d. Forms a precipitate with BaCl2 that does not dissolve in HNO.

Need answers to all these questions. Thanks in advance

Answer 1

1 &2 Some precipitation reactions are shown below.

3. Tests to distinguish between anions.

11 Ag Noz (aq) + Keli (as) Agcll + KNO3 bo symbol denotes precipitation 2) 2 KOH(aq) + Cacla (aq) → CaCOH)₂ + 2kd Can insoluble - Salt 3) AgNO3 Cos) + Nad (aa) 4) mg COH)₂ (s) + 2HCl (ag) Agol & + Nanga ingely (aq) + 21bol.

CO₃^2- and SO₄^2- can be distinguished by using dilute acids. Dilute sulfuric acid and even acetic acid can be used for this . When dilute acids were added to carbonates smalls bubbles starts emerging called as effervescence is formed. But sulfate won't give such reactions. To confirm whether the compound contain sulphate in it add BaCl₂ solution. If the solution turns forms white precipitate , it confirms the presence of sulfate in it forming BaSO₄ .

Cl^- and SO₄^2- can be distinguished by adding AgNO₃ solution. Chloride on reaction with silver nitrate gives white precipitate that won't given by sulfate.

CO₃^2- and Cl^- can be distinguished by using dilute acids. Carbonate on adding dilute acids gives effervescence but chloride will not.

4. Tests to distinguish between cations.

The given mixture of cations can be distinguished by flame tests. Small amount of sample is mixed with concentrated HCl and made into a paste. The paste is shown into a flame. Different colors can be shown by different anions.

B³⁺ gives a flame bright green.

Ca²⁺ produce an orange flame. Hence B³⁺ and Ca²⁺ can be distinguished by this way.

Ca²⁺ and Sr⁺ can also be distinguished by the same way. Here Sr⁺ produce a crimson red colour Thus can be easily distinguished.

Ca²⁺ and NH₄⁺ can also separately understood by the same flame test. In which ammonium ion will not respond to the flame test. While calcium ion can give orange colour to the flame.

5. Forms a precipitake with Ag Ng that does not dissolve is HNO. AgNO3 + Nach Ag clf+ Nanoz Agcl being insoluble in water precipitates out (as crody white preceptile whilst Nano being water soluble remains in soluson Addison of HNO₃ to this mixhoe would not bring about any change in the mixhre so far as the appesance of mixture is concerned as AgCl is Insoluble in waters or aqueous nitric and,

6 Forms a gas (bubbles) with Hcl but has no odour. Carbonate is the anions that fooms gas (bubbles) with HCl but has no odos. It is because of evolubons of co gas bubbles are formed. Na2CO3 + 2HCl(aq)) sodium a Naci (aq) + to + CO₂(g) Carbonate

yellow - green c) Gives a boight flame test. Ba 2+ Barum salts usually produce a green flame. Yellow-green, Apple green as time-green colors.
Sometimes barium produces a yellow flame without noticeable green color. The identity of anion depends mainly on the concentration also.

d,) SO₄^2- or the sulfate anion gives white precipitate on reaction with BaCl_2. The formation of white precipitate is due to BaSO₄ formed after the reaction.

Alz (SO4)+ 3Bacl PS > 2 Aldy + 3 Basou