Acids And Alkalis

Question 1

What are the classifications from the pH scale?

Answer 1

Strongly acidic (0-3), weakly acidic (4-6), neutral (7), weakly alkaline (8-10) a s strongly alkaline (11-14)

Question 2

Universal indicator

Answer 2

A combination of dyes that give the colours commonly shown on the pH scale. Add the indicator to a solution and compare the colour to a chart

Question 3

Litmus paper

Answer 3

Red in acidic solutions, purple in neutral solutions and blue in alkaline

Question 4

Phenolphthalein

Answer 4

Colourless in acidic solutions, bright pink in alkaline

Question 5

Methyl orange

Answer 5

Red in acidic solutions, yellow in alkaline

Question 6

What is an acid?

Answer 6

A source of hydrogen ions, proton donors

Question 7

What is an alkali?

Answer 7

Also known as bases, they can neutralise acids. They are proton acceptors, and a source of hydroxide ions

Question 8

Why is HCl acidic in water but not methylbenzene?

Answer 8

HCl dissolves in water to form H+ ions and so is acidic, but in methylbenzene HCl won’t dissolve and so won’t dissociate