A. STATE WHETHER THE FOLLOWING STATEMENTS ARE TRUE OR FALSE.
CORRECT THE FALSE STATEMENTS.
(a) All substances are either acidic or basic.
(b) A compound if acidic will turn all indicators red.
(c) Lime water turns red litmus blue.
(d) Common salt dissolved in water turns blue litmus red.
(e) Phenolphthalein is a natural indicator.
(f) Lemon water is basic in nature
B. FILL THE BLANKS IN THE FOLLOWING SENTENCES
(a) Lemon juice and vinegar taste ___________ because they contain ___________.
(b) Turmeric and litmus are _________ acid-base indicators.
(c) Phenolphthalein gives _________ colour with lime water.
(d) When an acidic solution is mixed with a basic solution, they _________ each other.
C. ANSWER THE FOLLOWING-
1. What are bases? What are their physical properties?
2. Give two uses of eacha. Calcium hydroxide
b. Ammonium hydroxide
3. What is an acid- base indicator? Give one example.
4. Name the base used to manufacture the soap.
D. MULTIPLE CHOICE QUESTIONS:
1. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would
be observed
(a) Yellow in both acid and base.
(b) Yellow in acid and red in base.
(c) Pink in acid and yellow in base.
(d) Red in acid and blue in base.
2. Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are
(a) Red and blue.
(b) Blue and red.
(c) Pink and colourless.
(d) Colourless and pink
3. Litmus’, a natural dye is an extract of which of the following?
(a) China rose (Gudhal)
(b) Beetroot
(c) Lichen
(d) Blue berries (Jamun)
4. A solution changes the colour of turmeric indicator from yellow to red. The solution is
(a) Basic
(b) Acidic
(c) Neutral
(d) Either neutral or acidic
5. Which of the following is an acid-base indicator?
(a) Vinegar
(b) Lime water
(c) Turmeric
(d) Baking soda
Answers
Explanation:
a false
b false
c false
d false
e false
f false
(a) Lemon juice and vinegar taste ___sour_____ because they contain _____acids______.
(b) Turmeric and litmus are __natural_______ acid-base indicators.
(c) Phenolphthalein gives __pink_______ colour with lime water.
(d) When an acidic solution is mixed with a basic solution, they ____neutralize_____ each other.
1. What are bases? What are their physical properties
ANSWER
Bases taste bitter, feel slippery,
It conduct electricity when dissolved in water.
Indicator compounds such as litmus can be used to detect bases. ...
The strength of bases is measured on the pH scale.
Bases lose their basicity when mixed with acids.
Bases react with acids to form salt and water.
2. Give two uses of eacha. Calcium hydroxide
b. Ammonium hydroxide
ANSWER
1) Ammonia is used in the fertilizers as solutions or salts. Ammonium hydroxide (NH4OH) is used in chemicals. 2) Ammonia is the base chemical in the manufacture of nitric .
3. What is an acid- base indicator? Give one example
ANSWER
Examples of acid-base indicators include litmus paper, phenolphthalein, and red cabbage juice. An acid-base indicator is a weak acid or weak base that dissociates in water to yield the weak acid and its conjugate base or else the weak base and its conjugate acid.
1. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would
be observed
ANSWER
The turmeric is acidic in nature and it is yellow in color. When turmeric paste is added to the acidic solution, it remains unchanged. The color in the acidic solution is yellow. When turmeric paste is added to the basic solution the yellow color changes to red color due to the neutralization reaction.
2. Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are
ANSWER
Phenolphthalein is a type of synthetic indicator which is colourless in acidic medium but gives pink colour in basic medium.
3. Litmus’, a natural dye is an extract of which of the following?
ANSWER
Lichen
Litmus is an extract of Lichen. Hence this is the correct answer.
4. A solution changes the colour of turmeric indicator from yellow to red. The solution is
ANSWER
Answer: Acids change turmeric powder from yellow to red so the solution muat be acidic. That the solution is base because turmeric paper turns Red when added to a base while remains Yellow in acid.
5. Which of the following is an acid-base indicator?
ANSWER
Turmeric is yellow in acidic and neutral solutions; is bright red in basic solutions. Hence, it is an acid-base indicator.
ᴀ ꜰᴀʟꜱᴇ
ʙ ꜰᴀʟꜱᴇ
ᴄ ꜰᴀʟꜱᴇ
ᴅ ꜰᴀʟꜱᴇ
ᴇ ꜰᴀʟꜱᴇ
ꜰ ꜰᴀʟꜱᴇ
(ᴀ) ʟᴇᴍᴏɴ ᴊᴜɪᴄᴇ ᴀɴᴅ ᴠɪɴᴇɢᴀʀ ᴛᴀꜱᴛᴇ ___ꜱᴏᴜʀ_____ ʙᴇᴄᴀᴜꜱᴇ ᴛʜᴇʏ ᴄᴏɴᴛᴀɪɴ _____ᴀᴄɪᴅꜱ______.
(ʙ) ᴛᴜʀᴍᴇʀɪᴄ ᴀɴᴅ ʟɪᴛᴍᴜꜱ ᴀʀᴇ __ɴᴀᴛᴜʀᴀʟ_______ ᴀᴄɪᴅ-ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀꜱ.
(ᴄ) ᴘʜᴇɴᴏʟᴘʜᴛʜᴀʟᴇɪɴ ɢɪᴠᴇꜱ __ᴘɪɴᴋ_______ ᴄᴏʟᴏᴜʀ ᴡɪᴛʜ ʟɪᴍᴇ ᴡᴀᴛᴇʀ.
(ᴅ) ᴡʜᴇɴ ᴀɴ ᴀᴄɪᴅɪᴄ ꜱᴏʟᴜᴛɪᴏɴ ɪꜱ ᴍɪxᴇᴅ ᴡɪᴛʜ ᴀ ʙᴀꜱɪᴄ ꜱᴏʟᴜᴛɪᴏɴ, ᴛʜᴇʏ ____ɴᴇᴜᴛʀᴀʟɪᴢᴇ_____ ᴇᴀᴄʜ ᴏᴛʜᴇʀ.
1. ᴡʜᴀᴛ ᴀʀᴇ ʙᴀꜱᴇꜱ? ᴡʜᴀᴛ ᴀʀᴇ ᴛʜᴇɪʀ ᴘʜʏꜱɪᴄᴀʟ ᴘʀᴏᴘᴇʀᴛɪᴇꜱ
ᴀɴꜱᴡᴇʀ
ʙᴀꜱᴇꜱ ᴛᴀꜱᴛᴇ ʙɪᴛᴛᴇʀ, ꜰᴇᴇʟ ꜱʟɪᴘᴘᴇʀʏ,
ɪᴛ ᴄᴏɴᴅᴜᴄᴛ ᴇʟᴇᴄᴛʀɪᴄɪᴛʏ ᴡʜᴇɴ ᴅɪꜱꜱᴏʟᴠᴇᴅ ɪɴ ᴡᴀᴛᴇʀ.
ɪɴᴅɪᴄᴀᴛᴏʀ ᴄᴏᴍᴘᴏᴜɴᴅꜱ ꜱᴜᴄʜ ᴀꜱ ʟɪᴛᴍᴜꜱ ᴄᴀɴ ʙᴇ ᴜꜱᴇᴅ ᴛᴏ ᴅᴇᴛᴇᴄᴛ ʙᴀꜱᴇꜱ. ...
ᴛʜᴇ ꜱᴛʀᴇɴɢᴛʜ ᴏꜰ ʙᴀꜱᴇꜱ ɪꜱ ᴍᴇᴀꜱᴜʀᴇᴅ ᴏɴ ᴛʜᴇ ᴘʜ ꜱᴄᴀʟᴇ.
ʙᴀꜱᴇꜱ ʟᴏꜱᴇ ᴛʜᴇɪʀ ʙᴀꜱɪᴄɪᴛʏ ᴡʜᴇɴ ᴍɪxᴇᴅ ᴡɪᴛʜ ᴀᴄɪᴅꜱ.
ʙᴀꜱᴇꜱ ʀᴇᴀᴄᴛ ᴡɪᴛʜ ᴀᴄɪᴅꜱ ᴛᴏ ꜰᴏʀᴍ ꜱᴀʟᴛ ᴀɴᴅ ᴡᴀᴛᴇʀ.
2. ɢɪᴠᴇ ᴛᴡᴏ ᴜꜱᴇꜱ ᴏꜰ ᴇᴀᴄʜᴀ. ᴄᴀʟᴄɪᴜᴍ ʜʏᴅʀᴏxɪᴅᴇ
ʙ. ᴀᴍᴍᴏɴɪᴜᴍ ʜʏᴅʀᴏxɪᴅᴇ
ᴀɴꜱᴡᴇʀ
1) ᴀᴍᴍᴏɴɪᴀ ɪꜱ ᴜꜱᴇᴅ ɪɴ ᴛʜᴇ ꜰᴇʀᴛɪʟɪᴢᴇʀꜱ ᴀꜱ ꜱᴏʟᴜᴛɪᴏɴꜱ ᴏʀ ꜱᴀʟᴛꜱ. ᴀᴍᴍᴏɴɪᴜᴍ ʜʏᴅʀᴏxɪᴅᴇ (ɴʜ4ᴏʜ) ɪꜱ ᴜꜱᴇᴅ ɪɴ ᴄʜᴇᴍɪᴄᴀʟꜱ. 2) ᴀᴍᴍᴏɴɪᴀ ɪꜱ ᴛʜᴇ ʙᴀꜱᴇ ᴄʜᴇᴍɪᴄᴀʟ ɪɴ ᴛʜᴇ ᴍᴀɴᴜꜰᴀᴄᴛᴜʀᴇ ᴏꜰ ɴɪᴛʀɪᴄ .
3. ᴡʜᴀᴛ ɪꜱ ᴀɴ ᴀᴄɪᴅ- ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀ? ɢɪᴠᴇ ᴏɴᴇ ᴇxᴀᴍᴘʟᴇ
ᴀɴꜱᴡᴇʀ
ᴇxᴀᴍᴘʟᴇꜱ ᴏꜰ ᴀᴄɪᴅ-ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀꜱ ɪɴᴄʟᴜᴅᴇ ʟɪᴛᴍᴜꜱ ᴘᴀᴘᴇʀ, ᴘʜᴇɴᴏʟᴘʜᴛʜᴀʟᴇɪɴ, ᴀɴᴅ ʀᴇᴅ ᴄᴀʙʙᴀɢᴇ ᴊᴜɪᴄᴇ. ᴀɴ ᴀᴄɪᴅ-ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀ ɪꜱ ᴀ ᴡᴇᴀᴋ ᴀᴄɪᴅ ᴏʀ ᴡᴇᴀᴋ ʙᴀꜱᴇ ᴛʜᴀᴛ ᴅɪꜱꜱᴏᴄɪᴀᴛᴇꜱ ɪɴ ᴡᴀᴛᴇʀ ᴛᴏ ʏɪᴇʟᴅ ᴛʜᴇ ᴡᴇᴀᴋ ᴀᴄɪᴅ ᴀɴᴅ ɪᴛꜱ ᴄᴏɴᴊᴜɢᴀᴛᴇ ʙᴀꜱᴇ ᴏʀ ᴇʟꜱᴇ ᴛʜᴇ ᴡᴇᴀᴋ ʙᴀꜱᴇ ᴀɴᴅ ɪᴛꜱ ᴄᴏɴᴊᴜɢᴀᴛᴇ ᴀᴄɪᴅ.
1. ᴛᴜʀᴍᴇʀɪᴄ ɪꜱ ᴀ ɴᴀᴛᴜʀᴀʟ ɪɴᴅɪᴄᴀᴛᴏʀ. ᴏɴ ᴀᴅᴅɪɴɢ ɪᴛꜱ ᴘᴀꜱᴛᴇ ᴛᴏ ᴀᴄɪᴅ ᴀɴᴅ ʙᴀꜱᴇ ꜱᴇᴘᴀʀᴀᴛᴇʟʏ, ᴡʜɪᴄʜ ᴄᴏʟᴏᴜʀꜱ ᴡᴏᴜʟᴅ
ʙᴇ ᴏʙꜱᴇʀᴠᴇᴅ
ᴀɴꜱᴡᴇʀ
ᴛʜᴇ ᴛᴜʀᴍᴇʀɪᴄ ɪꜱ ᴀᴄɪᴅɪᴄ ɪɴ ɴᴀᴛᴜʀᴇ ᴀɴᴅ ɪᴛ ɪꜱ ʏᴇʟʟᴏᴡ ɪɴ ᴄᴏʟᴏʀ. ᴡʜᴇɴ ᴛᴜʀᴍᴇʀɪᴄ ᴘᴀꜱᴛᴇ ɪꜱ ᴀᴅᴅᴇᴅ ᴛᴏ ᴛʜᴇ ᴀᴄɪᴅɪᴄ ꜱᴏʟᴜᴛɪᴏɴ, ɪᴛ ʀᴇᴍᴀɪɴꜱ ᴜɴᴄʜᴀɴɢᴇᴅ. ᴛʜᴇ ᴄᴏʟᴏʀ ɪɴ ᴛʜᴇ ᴀᴄɪᴅɪᴄ ꜱᴏʟᴜᴛɪᴏɴ ɪꜱ ʏᴇʟʟᴏᴡ. ᴡʜᴇɴ ᴛᴜʀᴍᴇʀɪᴄ ᴘᴀꜱᴛᴇ ɪꜱ ᴀᴅᴅᴇᴅ ᴛᴏ ᴛʜᴇ ʙᴀꜱɪᴄ ꜱᴏʟᴜᴛɪᴏɴ ᴛʜᴇ ʏᴇʟʟᴏᴡ ᴄᴏʟᴏʀ ᴄʜᴀɴɢᴇꜱ ᴛᴏ ʀᴇᴅ ᴄᴏʟᴏʀ ᴅᴜᴇ ᴛᴏ ᴛʜᴇ ɴᴇᴜᴛʀᴀʟɪᴢᴀᴛɪᴏɴ ʀᴇᴀᴄᴛɪᴏɴ.
2. ᴘʜᴇɴᴏʟᴘʜᴛʜᴀʟᴇɪɴ ɪꜱ ᴀ ꜱʏɴᴛʜᴇᴛɪᴄ ɪɴᴅɪᴄᴀᴛᴏʀ ᴀɴᴅ ɪᴛꜱ ᴄᴏʟᴏᴜʀꜱ ɪɴ ᴀᴄɪᴅɪᴄ ᴀɴᴅ ʙᴀꜱɪᴄ ꜱᴏʟᴜᴛɪᴏɴꜱ, ʀᴇꜱᴘᴇᴄᴛɪᴠᴇʟʏ ᴀʀᴇ
ᴀɴꜱᴡᴇʀ
ᴘʜᴇɴᴏʟᴘʜᴛʜᴀʟᴇɪɴ ɪꜱ ᴀ ᴛʏᴘᴇ ᴏꜰ ꜱʏɴᴛʜᴇᴛɪᴄ ɪɴᴅɪᴄᴀᴛᴏʀ ᴡʜɪᴄʜ ɪꜱ ᴄᴏʟᴏᴜʀʟᴇꜱꜱ ɪɴ ᴀᴄɪᴅɪᴄ ᴍᴇᴅɪᴜᴍ ʙᴜᴛ ɢɪᴠᴇꜱ ᴘɪɴᴋ ᴄᴏʟᴏᴜʀ ɪɴ ʙᴀꜱɪᴄ ᴍᴇᴅɪᴜᴍ.
3. ʟɪᴛᴍᴜꜱ’, ᴀ ɴᴀᴛᴜʀᴀʟ ᴅʏᴇ ɪꜱ ᴀɴ ᴇxᴛʀᴀᴄᴛ ᴏꜰ ᴡʜɪᴄʜ ᴏꜰ ᴛʜᴇ ꜰᴏʟʟᴏᴡɪɴɢ?
ᴀɴꜱᴡᴇʀ
ʟɪᴄʜᴇɴ
ʟɪᴛᴍᴜꜱ ɪꜱ ᴀɴ ᴇxᴛʀᴀᴄᴛ ᴏꜰ ʟɪᴄʜᴇɴ. ʜᴇɴᴄᴇ ᴛʜɪꜱ ɪꜱ ᴛʜᴇ ᴄᴏʀʀᴇᴄᴛ ᴀɴꜱᴡᴇʀ.
4. ᴀ ꜱᴏʟᴜᴛɪᴏɴ ᴄʜᴀɴɢᴇꜱ ᴛʜᴇ ᴄᴏʟᴏᴜʀ ᴏꜰ ᴛᴜʀᴍᴇʀɪᴄ ɪɴᴅɪᴄᴀᴛᴏʀ ꜰʀᴏᴍ ʏᴇʟʟᴏᴡ ᴛᴏ ʀᴇᴅ. ᴛʜᴇ ꜱᴏʟᴜᴛɪᴏɴ ɪꜱ
ᴀɴꜱᴡᴇʀ
ᴀɴꜱᴡᴇʀ: ᴀᴄɪᴅꜱ ᴄʜᴀɴɢᴇ ᴛᴜʀᴍᴇʀɪᴄ ᴘᴏᴡᴅᴇʀ ꜰʀᴏᴍ ʏᴇʟʟᴏᴡ ᴛᴏ ʀᴇᴅ ꜱᴏ ᴛʜᴇ ꜱᴏʟᴜᴛɪᴏɴ ᴍᴜᴀᴛ ʙᴇ ᴀᴄɪᴅɪᴄ. ᴛʜᴀᴛ ᴛʜᴇ ꜱᴏʟᴜᴛɪᴏɴ ɪꜱ ʙᴀꜱᴇ ʙᴇᴄᴀᴜꜱᴇ ᴛᴜʀᴍᴇʀɪᴄ ᴘᴀᴘᴇʀ ᴛᴜʀɴꜱ ʀᴇᴅ ᴡʜᴇɴ ᴀᴅᴅᴇᴅ ᴛᴏ ᴀ ʙᴀꜱᴇ ᴡʜɪʟᴇ ʀᴇᴍᴀɪɴꜱ ʏᴇʟʟᴏᴡ ɪɴ ᴀᴄɪᴅ.
5. ᴡʜɪᴄʜ ᴏꜰ ᴛʜᴇ ꜰᴏʟʟᴏᴡɪɴɢ ɪꜱ ᴀɴ ᴀᴄɪᴅ-ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀ?
ᴀɴꜱᴡᴇʀ
ᴛᴜʀᴍᴇʀɪᴄ ɪꜱ ʏᴇʟʟᴏᴡ ɪɴ ᴀᴄɪᴅɪᴄ ᴀɴᴅ ɴᴇᴜᴛʀᴀʟ ꜱᴏʟᴜᴛɪᴏɴꜱ; ɪꜱ ʙʀɪɢʜᴛ ʀᴇᴅ ɪɴ ʙᴀꜱɪᴄ ꜱᴏʟᴜᴛɪᴏɴꜱ. ʜᴇɴᴄᴇ, ɪᴛ ɪꜱ ᴀɴ ᴀᴄɪᴅ-ʙᴀꜱᴇ ɪɴᴅɪᴄᴀᴛᴏʀ.