Explore topic-wise InterviewSolutions in Current Affairs.

Sodium sulphate is a neutral salt because it is made from the strong acid and strong base.

Sodium carbonate is a basic salt because it is made from a strong base and a weak acid.

1. Sodium carbonate (washing soda) is used in glass, soaps and paper industries. 

2. It is used in the manufacture of sodium compounds such as borax. 

3. Sodium carbonate can be used” as a cleaning agent for domestic purposes. 

4. It is used for removing permanent hardness of water.

Sodium chloride – NaCl.

Sodium carbonate – Na₂CO₃ 

The aqueous solution of sodium chloride is neutral because it is formed from a strong acid and a strong base. The aqueous solution of sodium carbonate is basic because it gets hydrolysed to some extent and forms sodium hydroxide which is a strong base and carbonic acid which is a weak acid.

Washing soda is

sodium carbonate decahydrate. Properties:

(i) It is transparent crystalline solid.

(ii) It is soluble in water.

Uses:

(i) It is used for removing permanent hardness of water.

(ii) It is used in the manufacture of glass, soap and paper.

Basic component is the one that produces hydroxide (OH^-) ions when dissolved in water. In aqueous solution of ammonium chloride, ammonium ions (NH₄⁺) first associate with H₂O and form ammonia and hydroxide ions.

NH₄Cl + H₂O = NH₄⁺ + HCl ( equation 1) 

NH₄⁺ + H₂O = NH₃ + OH^- (equation 3)

Since ammonium ions produce hydroxide ions, NH₄⁺ are considered to be the basic components.

(a) Evaporation.

(b) Coal.

(c) Na₂CO₃ .10H₂O.

(d) Baking; washing.

(e) CaSO₄ . ?H₂O

Ammonium chloride is a salt of weak base and strong acid, it undergoes salt hydrolysis to produce an acidic solution whereas sodium chloride is a salt of strong acid and strong base, it does not undergo salt hydrolysis hence its solution remains neutral. 

Common salt is obtained from sea water by the process of evaporation.

Common salt occurs naturally in sea water and as rock salt.

Salt exists in two forms in nature i.e. in sea water and in the form of Halite a mineral rock of common salt. Common salt can be prepared by evaporation of sea water. Sea water is collected in division of land and it is allowed to evaporate under sunlight. Water is evaporated leaving behind mixtures of salt, form which common salt is separated by dissolving it in suitable reagent and then, recrystallizing salt from the solution.

Sodium chloride is required in our body for the working of nervous system, the movement of muscles, and the production of hydrochloric acid in the stomach.

Sodium hydroxide, sodium carbonate and sodium hydrogencarbonate.

2y² – 12y⁶ + 48y⁵ -9, बहुपद का घातांक सात है।

4x² + 3x -7, बहुपद का घातांक दो है।

7x⁵, बहुपद का घातांक पाँच है।

2x³ + 5x² -7, बहुपद का घातांक तीन है।

20x² + 12x²y²-10y²+20, बहुपद का घातांक तीन हैं।

3 × 6 × 9 × 12 × 15

= 3 × (3 × 2) × (3 × 3) × (3 × 4) × (3 × 5)

= (3⁵) (5 × 4 × 3 × 2 × 1)

= 3⁵ (5!)

(12/6)!

= 2!

= 2 × 1

= 2

\(\frac{9!}{3!6!}=\frac{9\times8\times7\times6!}{(3\times2\times1)\times6!}=84\)

\(\frac{12!}{6!}=\frac{12\times11\times10\times9\times8\times7\times6!}{6!}\)

= 12 × 11 × 10 × 9 × 8 × 7

= 665280

10! – 6!

= 10 × 9 × 8 × 7 × 6! – 6!

= 6! (10 × 9 × 8 × 7 – 1)

= 6! (5040 – 1)

= 6 × 5 × 4 × 3 × 2 × 1 × 5039

= 3628080

(10 – 6)!

= 4!

= 4 × 3 × 2 × 1

= 24

8!

= 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1

= 40320

Answer is (b) π/3

We know that two plane vector(r.n₁) = q₁ and vector(r.n₁) = q₂ are perpendicular to each other if and only if vector(n₁.n₂) = 0 

Here, vector n₁ = (i + 2j + 3k) and vector n₂ = (i + 2j - 7k)

Given that planes are perpendicular to each other

So, vector(n₁.n₂) = 0

(i + 2j + 3k).(λi + 2j - 7k) = 0

1 x λ + 2 x 2 + 3 x -7 = 0

λ = 17

Hence, require value of λ is 17 

For binomial distribution,

mean = nP = 12 and variance = npq = 3

12q = 3 

q = 1/4

∴ P = 1 - q = 1 - (1/4) = 3/4

and n.p = 12

n.(3/4) = 12

n = 16

∴ Binomial distribution is

(P + q)ⁿ = ((3/4) + (1/4))¹⁶

The direction ratio of two lines are given by(a₁,b₁,c₁) = (-3,2k,2) and (a₂,b₂,c₂) = (3k,1,-5)

If the two lines perpendicular than a₁a₂ + b₁b₂ + c₁c₂ = 0

(-3)(3k) + (2k) 1 + (2)(-5) = 0

-9k + 2k - 10 = 0

= -7k - 10 = 0

7k = -10

∴ k = -10/7

Copper metal slowly reacts with water, carbon dioxide and oxygen present in air to form basic copper carbonate which is green in colour. Its layer slowly gets deposited on the surface of the metal. Now as lemon is acidic, hence when we rub the tarnished copper vessel with lemon, the basic copper oxide or copper carbonate reacts with the acid present in lemon to form a salt which is washed away with water.

(i) Metals conduct electricity because they have electrons which are free to move. They offer little resistance to the flow of current. Silver and copper are the best conductors of electricity. 

(ii) Reaction of metals with nitric acid does not evolve hydrogen gas. It is because HNO₃ is a strong oxidising agent. It oxidises H, to produce water and itself gets reduced to any of its oxides such as N₂O, NO or NO₂. 

(iii) Pure gold is 24carat and is very soft. Therefore, it is not suitable for making jewellery. It is alloved with Cu or Ag to make it hard. Generally, 22 carat gold is used for making ornaments, which contains 22 parts of pure gold and 2 paris of either Cu or Ag

(i) Metals conduct electricity because they have electrons which are free to move. They offer little resistance to the flow of current. Silver and copper are the best conductors of electricity. 

(ii) Reaction of metals with nitric acid does not evolve hydrogen gas. It is because HNO₃ is a strong oxidising agent. It oxidises H₂ to produce water and itself gets reduced to any of its oxides such as N₂O, NO or NO₂. 

(iii) Pure gold is 24carat and is very soft. Therefore, it is not suitable for making jewellery. It is alloyed with Cu or Ag to make it hard. Generally, 22 carat gold is used for making ornaments, which contains 22 parts of pure gold and 2 parts of either Cu or Ag

1. (i) Less than 7

2. (iii) 7

3. (i) Hydrochloric Acid

4. (iii) All of the above

5. (i) Water

1. (i) Hydrochloric acid

2. (ii) Too much of acid

3. (ii) Pain and irritation

4. (i) Antacids

5. (ii) Milk of magnesium

Given:

Mass of solute(NaCl) = 40g

Mass of solvent(water) = 100ml = 100g

Mass of solution = 40+100 = 140g

Concentration of the solution in terms of mass percentage is given as,

Concentration of solution = Mass of solute/Mass of solution×100

40/140×100= 28.57%

Hence the Concentration of solution = 28.57%

1) Solid Carbon dioxide 

2) Naphthalene 

Explanation: Both these substances are solids and directly evaporate into their gaseous state depending on the temperature and pressure of the environment in which they are placed. Generally, these substances are solid at lower temperatures and evaporate into their gaseous state when the temperature increases.

Miss Anne Sullivan was Helen’s instructor as well as a teacher. She was sent by the Perkins Institution in Boston to teach Helen. They found her competent enough to begin Helen’s education and Anne arrived at Helen’s place in March.

After her arrival, Helen’s life changed. Apart from being a guide and instructor, she was like a mother to Helen. She accompanied her wherever she went.

Miss Sullivan had a great amount of patience. Sometimes Helen used to throw tantrums but Miss Sullivan always handled her very well. She taught her to communicate by writing the spellings of the words on her hand with her fingers. Helen learnt this art and was able to communicate with others in an effective way, and she learnt to write sentences also.

Miss Sullivan was a perfect teacher who enjoyed spending her time with Helen. She taught her subjects like Arithmetic, History, Geography, Zoology, Botany, etc., through a playful method. Helen never realised that she was being educated during the process of learning. She enjoyed all the lessons with Miss Sullivan. Both Helen and Miss Sullivan had a good time with each other throughout their lives.

Value Points :

• Regarded her as an intruder initially.
• Jealous of her—she ceased to be mother's only darling.
• Discovered Mildred sleeping in her doll's cradle—overturned it—Luckily mother caught her in time.
• Later signs of bonding
• Couldn't understand her, she could not understand finger language. Yet grew in understanding and love.

Detailed Answer :

Mildred Keller was Helen’s younger sister. Before she was born, Helen used to get all the attention of her parents but with Mildred’s birth, things changed a bit and Helen became jealous of her but later both of them became very close to each other. Mildred was an alert and observant child. Once they were at Fern Quarry. They went out to gather persimmons and got lost in woods. It started getting dark but they were unable to find their way back home. On the way, Mildred observed a trestle and realised that it was a shortcut to their home. So, they all started walking on that path. Suddenly, she saw a train moving towards them. She alerted Helen and both of them were lucky enough to climb down in time. The train zoomed past them. It was Mildred’s alertness which had saved something terrible from happening.

Charge of Plagiarism 

• She was accused of plagiarising ‘The Frost Fairies’ by Ms. Margaret T. Canby in her story ‘The Frost King’.

• She was accused of not telling an original story.

• She was unaware of plagiarism in any form.

• It shook her confidence.

• It demotivated her.

• It left her demoralized.

• Ms. Sullivan helped and consoled her, restored her self-confidence, persuaded her to write for the Youth’s Companion a brief account of her life.

• Lost her dearest friend, Mr. Anagnos of the Perkins Institute for the blind.

Detailed Answer :

When Helen was summoned by the investigative body to answer on the charges of plagiarism, she was very distressed. In the beginning, she pleaded innocence and assured that she could not recall Miss Canby’s The Frost Fairies’ being read out to her. Miss Sullivan also had not even heard of the book called ‘Birdie and his Friends.’ Later, it was found that Ms. Sophie had read many books to Helen in Anne’s absence. Whereas, Mr. Anagnos thought that Helen and Miss Sullivan had copied someone else’s stories to impress him.

She found that irrespective of her explanations, the committee had already decided that Helen had copied ‘The Frost King’ from Miss Margaret T. Canby’s ‘Frost Fairies’. This had frightened Keller so much that she refused to resume writing. Even while writing letters to her mother, she would double-check them to ensure that each and every word or expression was her own creation. She was very upset and got many consolations. Even Miss Canby kindly sent her a letter. But still this was a black cloud in Helen’s garden of childhood.

This incident shook Helen’s confidence. It demotivated her and left her demoralised. It was at this stage that Miss Anne Sulivan came to her rescue again. She consoled and helped restore her self-confidence. Miss Sullivan persuaded her to write for the Youth’s Companion—a brief account of her life. Helen did so hesitatingly. But this incident made her lose her dearest friend Mr. Anagnos also because Helen had dedicated her book to him on his birthday, but he never stood by her throughout the court activities.

Value Points :

• Helen gave violets to her teacher.
• Teacher kissed her and said ‘I love Helen’.
• When Helen questioned her about love, she pointed to her heart indicating that it was here that love resided.
• Couldn’t understand it as she couldn’t touch it.
• Thought love was the sweetness of violets or the warmth of the sun.
• Thought it strange that the teacher couldn’t show her love.
• Soon realized that it couldn’t be touched, could only be felt.

Detailed Answer :

Helen’s teacher, Miss Sullivan, taught her everything. She came as a ray of hope into her life. Helen was very happy and excited in her company. One day, she gave violets to her teacher. Miss Sullivan kissed her and said, ”I love Helen’. Helen couldn’t understand the meaning of love. So, she questioned her about it. Miss Sullivan pointed to her heart indicating that it was where love resided. Helen still couldn’t understand it as it was an abstract thing which she couldn’t touch. She thought that the love was the sweetness of violets, the warmth of the sun but her teacher replied in negative. Helen felt quite strange that Miss Sullivan was unable to show her love. Soon, it started drizzling. Miss Sullivan again pointed it out to Helen. Immediately, Helen realized that love is something which can’t be touched. It is an emotion, something which can only be felt with heart.

Value points :

Helen’s relation with Dr. Bell

Dr. Bell exposed her to a new world, new sensations, discoveries, travels etc. 

interacted with nature and people more than before 

inculcated scientific curiosity - visit to Niagara Falls

Detailed Answer : Alexander Graham Bell, the inventor of the telephone was a good friend and companion of Helen. He was a great support to Helen Keller. He held a special place in her life. Helen spent many days with him in Washington. She was interested in his experiments and presentation of different theories in an interesting way. Dr. Bell exposed her to a new world. He told her about new sensations, new discoveries, travels etc. She visited the World Fair where Dr. Bell told her the detailed functions of devices like telephones, autophones, phonographs and many other scientific inventions. All these added to her knowledge and vocabulary. She visited the Niagara Falls also where she was accompanied by Miss Anne Sullivan and Dr. Graham Bell. He inculcated scientific curiosity in her. Helen was so impressed with Dr. Bell that she dedicated her autobiography to him. 

Value Points :

• Mildred Keller—Helen's younger sister
• Initial jealousy, later became close to her
• While at Fern Quarry—went to gather persimmons with her.
• Got lost in woods
• Mildred alert—observed trestle-shortcut home.
• Suddenly saw train—Luckily they climbed down in time

Detailed Answer : Helen had a younger sister called Mildred. Before her birth, Helen was the darling daughter of her parents. But after the arrival of Mildred, she had ceased to be so. As a result she started treating Mildred as an intruder. The thought of Mildred receiving more love from her mother filled Helen with jealousy. Mildred took her place in her mother’s lap and took up all the care and time of her mother which was not acceptable to Helen. Her jealousy reached its height when Helen saw Mildred sleeping peacefully in her doll’s cradle. She became angry and showed her anger by overturning the cradle. It was only her mother’s timely intervention that saved her from falling. With the passage of time, this jealousy turned into an affectionate relationship. The signs of bonding could be seen very clearly. Mildred could not understand her sign language yet understanding and love grew between both of them. Affection grew in their hearts and they went hand in hand wherever they went.

Value points :

Helen’s visit to the Niagra Falls

• Her visit to Niagara Falls an eye-opener

 • Could feel the glory of nature through vibrations and other sensory perceptions.

• Felt great ; humbled.

Detailed Answer : 

The chief incident of the year 1893 was when Helen went to Washington during the inauguration of President Cleveland and her visit to Niagara falls and the World’s Fair. Helen’s visit to the Niagara Falls was an eye-opener for her. It was very difficult to describe the emotions produced in her heart while she stood near the Niagara Falls and ‘felt the air vibrate and the earth tremble’. She was accompanied by Miss Sullivan and Dr. Graham Bell. Whenever she described her visit to Niagara and its beauties, people would ask her in wonder ‘What did the beauties of Niagara mean to her when she could neither see the waves rolling up the beach nor hear their roar ?’ But when she saw Niagara she could feel the glory of nature through vibrations and other sensory perceptions. She felt great and humbled on that day.

C) Primary sector

correct option is A) Service

C) Heavy competition

B) Fruit seller

(i)  Vegetable vendor

• The remaining three are the occupations of educated skilled labour. 
• Vegetable vendor need not have education.

(ii) Cobbler

• The remaining three are government servants. 
• Cobbler is self-employed person.

Yes, this story can partially be classified as surrealistic. The main protagonist’s illogical and uncontrolled association of mind support this view. Dr Margolin’s thoughts make us aware of his past and its impact on his present. In the story the author tells us about the childhood of Margolin, his love with Raizel, and his married life with someone else than his beloved. Dr Margolin has an illusionary encounter with Raizel and wants to fulfil his suppressed desire of getting married with his beloved Raizel. Hence the entire atmosphere in the story is illusionary that allows it to be classified as surrealistic.

हाँ, कहानी को आंशिक रूप से surrealistic (स्वप्न जैसी) श्रेणी में वर्गीकृत किया जा सकता है। कहानी के मुख्य पात्र डॉ. मारगोलिन के मस्तिष्क के अतार्किक व अनियंत्रित विचार इस तत्व का समर्थन करते हैं। डॉ मारगोलिन के विचार हमें उसके भूतकाल (past life) और वर्तमान जीवन पर इसके प्रभाव से अवगत कराते हैं। इस कहानी में लेखक हमें मारगोलिन के बचपन, रायज़ल के साथ उसके प्रेम, और उसके विवाहित जीवन के विषय में बताता है। डॉ मारगोलिन का रायज़ल से भ्रामक (illusionary) सामना या मुलाकात होती है। और वह रायज़ल के साथ अपने विवाह की दमित इच्छा को पूरा करना चाहते हैं। अतः सारी कहानी में वातावरण भ्रामक अथवा काल्पनिक है, जिस कारण इसे surrealistic श्रेणी में वर्गीकृत किया जा सकता है।

‘Dr Margolin suffered from hypochondria because he had been shocked by the mindless massacre of Jews and extinction of his family. It had destroyed all his faith in humanity and rooted out his last hope of better days. All these incidents filled his mind with pessimism and later on developed into hypochondria. ‘Besides this, he did not believe in God which could have relieved him from his depression. He always brooded over his dark past which aggravated his problem. The memories of his beloved killed by Nazis were filled in his mind.

डा. मारंगोलिन यहूदियों के सामूहिक नरसंहार एवं अपने परिवार के विनाश से स्तब्ध रह गये थे। इससे उनका मानवता पर से विश्वास समाप्त हो गया था और अच्छे दिनों की उम्मीद को पूर्ण रूपेण समाप्त कर दिया था। इन सभी घटनाओं ने उनके दिमाग को निराशावाद से भर दिया था और जो कि बाद में बीमारियों के भय की.. बीमारी में परिवर्तित हो गया था। इसके अतिरिक्त वह ईश्वर पर भी विश्वास नहीं करते थे जिससे उनको अवसाद से आराम मिलता। वह हमेशा भूतकाल के बुरे दिनों के बारे में सोचते रहते थे जिससे समस्या और ज्यादा गम्भीर हो गई। नाजियों द्वारा मारे गये उसके प्रिय लोगों की यादें उसके मस्तिष्क में भरी हुई थीं।

According to Jewish law, Dr Margolin was unmarried because he and Gretl had only a civil ceremony.

यहूदी कानून के अनुसार, डा. मारगोलिन अविवाहित थे क्योंकि उन्होंने तथा ग्रेट्ल ने केवल नागरिक समारोह किया था।