Qualitative Analysis for Chemistry

bonkysleuth SG

when you add concentrated H2SO4 into solid ammonium chloride, you get a gas (Hydrogen chloride). when hydrogen chloride is added to ammonia gas, a white fume forms. may i know the identity of the white fume?

hydrogen chloride -----(oxidising agent)-----> yellow/green gas (chlorine)-------(potassium iodide, aq)----> red/brown solution and black solid.

what is the red/brown solution?

and may i know what solid do you add to ammonium chloride to form ammonia? it cant be hydrogen chloride since it is a gas.

Please help explain. thanks.

UltimaOnline SG

hydrogen chloride -----(oxidising agent)-----> yellow/green gas (chlorine)-------(potassium iodide, aq)----> red/brown solution and black solid.

what is the red/brown solution?

and may i know what solid do you add to ammonium chloride to form ammonia? it cant be hydrogen chloride since it is a gas.

Please help explain. thanks.

>>> when hydrogen chloride is added to ammonia gas, a white fume forms. may i know the identity of the white fume? <<<

NH4Cl(s). Many small droplets form "fumes".

>>> hydrogen chloride -----(oxidising agent)-----> yellow/green gas (chlorine)-------(potassium iodide, aq)----> red/brown solution and black solid. what is the red/brown solution? <<<

I2(aq) red/brown solution.

I2(s) black solid.

>>> and may i know what solid do you add to ammonium chloride to form ammonia? it cant be hydrogen chloride since it is a gas. <<<

Any solid hydroxide (eg. calcium hydroxide).

OH- + NH4+ ---> NH3 + H2O

bonkysleuth SG

>>> when hydrogen chloride is added to ammonia gas, a white fume forms. may i know the identity of the white fume? <<<

NH4Cl(s). Many small droplets form "fumes".

>>> hydrogen chloride -----(oxidising agent)-----> yellow/green gas (chlorine)-------(potassium iodide, aq)----> red/brown solution and black solid. what is the red/brown solution? <<<

I2(aq) red/brown solution.

I2(s) black solid.

>>> and may i know what solid do you add to ammonium chloride to form ammonia? it cant be hydrogen chloride since it is a gas. <<<

Any solid hydroxide (eg. calcium hydroxide).

OH- + NH4+ ---> NH3 + H2O

oo, thanks. but may I know why the red/brown solution formed is I2 when another form of I2 in solid has already been formed?

and I was thinking whether adding Ca(OH)2 to ammonium chloride is appropriate since Ca(OH)2 is classified as AQUEOUS in my textbook. but it is slighly soluble only, isnt it?

davidche SG

oo, thanks. but may I know why the red/brown solution formed is I2 when another form of I2 in solid has already been formed?

and I was thinking whether adding Ca(OH)2 to ammonium chloride is appropriate since Ca(OH)2 is classified as AQUEOUS in my textbook. but it is slighly soluble only, isnt it?

sparingly soluble yo. I think it shld be in your oxide section tat the textbook mention that.

UltimaOnline SG

oo, thanks. but may I know why the red/brown solution formed is I2 when another form of I2 in solid has already been formed?

and I was thinking whether adding Ca(OH)2 to ammonium chloride is appropriate since Ca(OH)2 is classified as AQUEOUS in my textbook. but it is slighly soluble only, isnt it?

Yes, as davidche already pointed out, the answer to both your questions above, is that both I2 and Ca(OH)2 are both partially soluble in water.

Which is why you have both solid and aqueous iodine, and you have both solid and aqueous calcium hydroxide.

Solid calcium hydroxide is called slaked lime.

Aqueous calcium hydroxide is called lime water.

Any further questions, bonkysleuth?

bonkysleuth SG

Yes, as davidche already pointed out, the answer to both your questions above, is that both I2 and Ca(OH)2 are both partially soluble in water.

Which is why you have both solid and aqueous iodine, and you have both solid and aqueous calcium hydroxide.

Solid calcium hydroxide is called slaked lime.

Aqueous calcium hydroxide is called lime water.

Any further questions, bonkysleuth?

absolutely no. thanks. (=