Indicators

Q. China rose indicator in acidic solution changes its colour to ________________.

1. yellow
2. dark pink
3. green
4. blue

Q. Which of the following indicator gives pink colour in a basic solution?

1. Methyl orange
2. Turmeric
3. Phenolphthalein
4. Litmus paper

Q. Ram was given a jar filled with distilled water. What would be his observation when he adds a drop of phenolphthalein in this jar?

1. Water turns red in colour
2. Water turns blue in colour
3. Water remains colourless
4. Water turns pink in colour

Q.

Which colour does a turmeric turn into in the presence of bases?

Q.

Bases turn the yellow turmeric paper

1. blue

2. green

3. orange

4. red

Q. The set of natural acid-base indicators is

प्राकृतिक अम्ल-क्षारक सूचकों का समुच्चय है

1. Turmeric and methyl orange
   
   हल्दी तथा मेथिल ऑरेन्ज
2. Phenolphthalein and petals of petunia
   
   फीनॉल्फ्थेलिन तथा पेटूनिया के फूलों की पंखुड़ियाँ
3. Red cabbage leaves and onion
   
   लाल पत्ता गोभी तथा प्याज
4. Litmus and dock plant leaves
   
   लिटमस तथा डॉक पौधे की पत्तियाँ

Q. Name the source from which litmus solution is obtained. What is the use of this solution?

Q. Write any four indicators and how they change their colour in an acidic medium?

Q. Which of the following is a naturally occuring indicator?

1. Methyl orange
2. Turmeric
3. Phenolphthalein
4. Methyl red

Q. Three test tubes contains different solutions and are labelled as A, B and C. The table below shows the observations when red and blue litmus papers were dipped in these test tubes.
Analyse the table given below and choose the correct options from the following.

$\begin{array}{cccc}& \text{Test tube A}& \text{Test tube B}& \text{Test tube C}\\ \text{Red Litmus}& \text{No change}& \text{No change}& \text{No change}\\ \text{Blue Litmus}& \text{Red}& \text{No change}& \text{Red}\end{array}$

1. The sample in test tube A is acidic
2. The sample in test tube A is neutral
3. The sample in test tube C is acidic
4. The sample in test tube B is neutral

Q. What would be the colour change observed when a turmeric stained cloth is washed with soap?​

1. Yellow to Blue
2. Yellow to colourless
3. Yellow to pink
4. Yellow to red​

Q. ____ is the reaction between an acid and a base.

1. Acid hydrolysis
2. Hydrolysis
3. Neutralization
4. Alkalisation

Q. A universal indicator is made by dissolving methyl orange, bromothymol blue and phenolphthalein in alcohol. Which of the following processes could best be used to separate the methyl orange component from the universal indicator solution?

1. Chromatography
2. Distillation
3. Filtration
4. Decantation

Q. Lemons and vinegar are acidic in nature. They taste .

1. salty
2. sour
3. bitter

Q. Which of the following are not natural indicators?

1. Methyl orange
2. Turmeric
3. Litmus
4. Phenolphthalein

Q. Write any four indicators and how they change their colour in an acidic medium? [2 marks]

Q. Turmeric stain on a shirt changes to ______ colour, when it is washed with soap.

1. red
2. blue
3. yellow
4. white

Q. The pH of two solutions A and B are 11 and 7.7, respectively. What can you say about the nature of these solutions?

1. A is weakly acidic and B is strongly basic.
2. Both A and B are strongly acidic.
3. A is strongly acidic and B is weakly acidic.
4. A is strongly basic and B is weakly basic.

Q. Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively.
Arrange the pH of the solutions in increasing order of hydrogen-ion concentration.

Q. ____ is the reaction between an acid and a base.

1. Neutralization
2. Alkalisation
3. Acid hydrolysis
4. Hydrolysis

Q. Which of the following solutions will resist change in pH upon addition of small quantity of water?

1. Chemical pH indicator
2. Acid/base buffer
3. Anhydrous solution
4. Hypotonic solution
5. Supersaturated solution

Q. ____ is the reaction between an acid and a base.

1. Hydrolysis
2. Neutralization
3. Alkalisation
4. Acid hydrolysis

Q. Which amongst the following is a source of saltwater?

1. Ocean
2. Glacier
3. Pond
4. River

Q. Which of the following is a naturally occuring indicator?

1. Phenolphthalein
2. Methyl red
3. Turmeric
4. Methyl orange