The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are?
Na2SO4 + SO2 + O2 + H2O
Na2SO3 + SO3 + O2 + H2O
Na2SO4 + SO2 + S + H2O
Na2SO4 + SO3 + S + H2O
Na2SO4 + SO2 + H2O only
Correct answer is C
\(Na_2S_2O_3 + H_2SO_4 → Na_2SO_4 + SO_2 + S↓ + H_2O\). Sodium thiosulfate reacts with sulfuric acid to produce sodium sulfate, sulphur dioxide, sulfur, and water.
All the compounds are gaseous at 20 °C
One of the compounds is gaseous at 20 °C
Two of the compounds are gaseous at 20 °C
Three of the compounds are gaseous at 20 °C
None of the compounds is gaseous at 20 °C
Correct answer is D
No explanation has been provided for this answer.
48,000
96,000
192,000
384,000
576,000
Correct answer is D
48,000 coulombs are required to discharge 0.5 mole of Na
∴ 1 m will be discharged by 2 x 48,000 = 96,000 coulombs
2 moles of Na will be discharged by 2 x 96,000
= 192,000
For lead (Pb) two electrons are involved.
∴ Number or coulombs required to discharged 2 moles of Pb = 2 x 192,000 = 384,000 coulombs
28.8 cm3 of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is?
17.4 cm3
14.7 cm3
27.3 cm3
31.7 cm3
Correct answer is C
(V1)/(T1) = (V2)/(T2) (288 cm3)/(288) = (V2)/(273)
V2 = (288 x 273)/(288) = 273 cm3
Which of the following statements about phosphorus is NOT correct?
Phosphorus is a solid mineral
Phosphorus is obtained by oxidation reaction of phosphate
Phosphorus exists in two allotropic forms
Both forms of phosphorus are interconvertible
Yellow phosporus ignites when rubbed on a rough surface
Correct answer is C
The main allotropes of phosphorus include the white phosphorus, red phosphorus and black phosphorus.