1. Four particles are present in dilute sulfuric acid.
Which particle is present in the lowest concentration?
A The hydroxide ion. OH– (aq)
B The hydrogen ions, H+(aq)
C The sulfate ion. SO42-(aq)
D The water molecule. H2O(l)
2. The following statements about dilute sulfuric acid are all correct.
- A white precipitate is formed when aqueous barium chloride is added.
- The solution turns anhydrous copper (II) sulfate from white to blue.
- Addition of Universal indicator shows that the solution has a pH value of lesser than 7.0
- The solution reacts with copper (II) oxide, forming a blue solution.
Which two statements confirm the acidic nature of the solution?
A 1 and 2
B 1 and 3
C 2 and 4
D 3 and 4
3. 2 drops of methyl orange are added to 15 cm3 of dilute nitric acid in a conical flask. 10 cm3 of aqueous potassium hydroxide are then added gradually to the flask. Which changes occurs in the mixture in the conical flask?
A Methyl orange changes colour from orange to red.
B The concentration of the H+ ion decreases.
C The pH value is lowered.
D White precipitate is formed.
4. X, Y and Z are elements in the same period of the Periodic Table. X forms an acidic oxide, Y forms a basic oxide and Z forms an amphoteric oxide. If X, Y and Z are placed in order of increasing atomic number, which order is correct?
A X, Y, Z
B X, Z, Y
C Y, X, Z
D Y, Z, X
5. Which observation is true when an alkaline solution of potassium nitrate is warmed with aluminium powder?
A Colourless and odourless gas is evolved. Gas relights glowing splinter.
B Colourless and pungent gas is evolved. Gas turns moist red litmus paper blue.
C Colourless and odourless gas is evolved. Lighted splinter extinguishes with ‘pop’ sound.
D Colourless and pungent gas is evolved. Gas turns acidified potassium dichromate (VI) from orange to green.