Acids, Bases and Indicators
Questions about acids, bases, natural and chemical indicators, and neutralization reactions including color changes with litmus and phenolphthalein
Questions
A group of students was doing an experiment using sodium hydroxide and dilute hydrochloric acid. They added phenolphthalein indicator, which gave the solution a pink colour. As more and more dilute hydrochloric acid was added to it, drop by drop, at one point a colour change was noted. This happened due to neutralisation reaction. The colour changes from pink to _________.
- blue
- green
- red
- violet
- colourless
A group of students was given three solutions and strips of red and blue litmus paper. They were asked to find out which solution was neutral. Which of the following is the correct identification?
- Red litmus turns blue
- No change with red or blue litmus paper
- Blue litmus paper remains blue
- Violet colour appears on the litmus paper
- Colour changes to green
In a reaction between acid and base, a lot of heat is evolved, with the formation of water and __________.
- salt
- vitamin
- fibres
- minerals
- antacids
Litmus paper is a natural indicator. From where is it obtained?
- Lichen
- Turmeric
- Red cabbage
- China rose
- Coffee powder
A group of children was playing, and they wanted to get a particular colour for completing a painting. In order to get this colour fast, they mixed two easily available items in their house; turmeric powder and soap liquid. Which colour did they get by this?
- Green
- Black
- Red
- Blue
- Purple