उत्पादन से तात्पर्य है कि वर्तमान समय में वस्तु का मौजूद होना विद्यमान रहना या किसी वस्तु को समायोजित करके बनाना उत्पादन कहलाता है यह उत्पाद भी कहलाता है।

उपभोग से आशय यह है वस्तु का उपयोग (इस्तेमाल )करने के बाद विद्यमान नहीं होना या समाप्त हो जाना उपभोग कहलाता है या भविष्य में नष्ट हो जाना या रूप परिवर्तित हो जाना वह भी उपभोग कहलाता है उपभोग को अनेक प्रकार से समझाया जा सकता है समझा जा सकता है ।

Policy to hide: The strategy for states 'to hide' implies that the states should remain away from the dominant power. Practically, however, it is not possible for mega-states to follow this policy for any substantial length of time.

Colloidal solutions of gold prepared by different methods are of different colours because of different diameters of colloidal gold particles. The colour of colloidal solutions depends upon the size of the colloidal particles.

Laboratory Preparation of Nitric Acid

In the laboratory, nitric acid can be prepared by heating sodium or potassium nitrate with concentrated sulphuric acid to about 423-475 K.

NaNO₃ + H₂SO₄ ——> NaHSO₄ + HNO₃

Anhydrous nitric acid can be obtained by distillation of concentrated aqueous nitric acid with P₄0₁₀.

Manufacture of Nitric Acid
 

Nitric acid is commonly manufactured by Ostwald process in which it is prepared by the catalytic oxidation of ammonia by atmospheric oxygen. The reaction is carried out at about 500 K and 9 x 10⁵ Pa (9 bar) pressure in the presence of Pt or Rh gauge as catalyst.

4NH₃(g) + 50₂(g)——> 4NO(g) + 6H₂0(g)    ΔH =- 90.2 kJ

Pt/Rh gauge,  500K, 9 bar

Nitric oxide thus formed combines with oxygen to form nitrogen dioxide.

2NO(g) +  O₂ (g) ——> 2 NO₂ (g) 

Nitrogen dioxide so formed, dissolves in water to give nitric acid.

3NO₂ (g) + H₂O(l) —–> 2HNO₃(aq) + NO(g)

Dilute nitric acid is further concentrated by dehydration with concentrated sulphuric acid to get about 98% acid.

Properties of Nitric Acid

Physical Properties

1) Pure nitric acid is a colourless liquid.

2) It has boiling point 355.6 K and freezing point 231.4 K.

3) laboratory grade nitric acid contains about 68% of HNO₃ by mass and has a specific gravity of 1.504.

4) The impure acid is generally yellow due to the presence of nitrogen dioxide as impurity. Nitric acid containing dissolved nitrogen dioxide is known as fuming nitric acid.

5) It has a corrosive action on skin and produces painful blisters.

Chemical Properties

(1) Acidic character: It is one of the strongest acids because it is highly ionised in aqueous solution giving hydronium and nitrate ions.

2HNO₃(aq) +H₂O (l) ——> H₃O⁺ + NO₃¯(aq)

It turns blue litmus red. It forms salts with alkalies, carbonates and bicarbonates.

NaOH + HNO₃ —-> NaNO₃ + H₂O

Na₂CO₃ +  HNO₃ —-> 2NaNO₃ + H₂O + CO₂

NaHCO₃ + HNO₃ —-> NaNO₃ + H₂O + CO₂

(2) Action on metals: With the exception of gold and platinum, nitric acid attacks all metals forming a variety of products. The product depends upon the nature of metal, the concentration of acid and temperature.

(A) Metals that are more electropositive than hydrogen (Mg, Al, Mn, Zn, Fe, Pb, etc.). In this case nascent hydrogen is liberated which further reduces nitric acid.

M + 2HNO₃ ——> M(NO₃)₂ + 2H

HNO₃ + H —-> Reduction product + H₂O

The principal product is NO₂, with conc. HNO₃, N₂O with dil. HNO₃, and ammonium nitrate with very dil. HNO₃.

For example: Zn reacts as:

Laboratory Preparation of Nitric Acid

In the laboratory, nitric acid can be prepared by heating sodium or potassium nitrate with concentrated sulphuric acid to about 423-475 K.

NaNO₃ + H₂SO₄ ——> NaHSO₄ + HNO₃

Anhydrous nitric acid can be obtained by distillation of concentrated aqueous nitric acid with P₄0₁₀.

Manufacture of Nitric Acid
 

Nitric acid is commonly manufactured by Ostwald process in which it is prepared by the catalytic oxidation of ammonia by atmospheric oxygen. The reaction is carried out at about 500 K and 9 x 10⁵ Pa (9 bar) pressure in the presence of Pt or Rh gauge as catalyst.

4NH₃(g) + 50₂(g)——> 4NO(g) + 6H₂0(g)    ΔH =- 90.2 kJ

Pt/Rh gauge,  500K, 9 bar

Nitric oxide thus formed combines with oxygen to form nitrogen dioxide.

2NO(g) +  O₂ (g) ——> 2 NO₂ (g) 

Nitrogen dioxide so formed, dissolves in water to give nitric acid.

3NO₂ (g) + H₂O(l) —–> 2HNO₃(aq) + NO(g)

Dilute nitric acid is further concentrated by dehydration with concentrated sulphuric acid to get about 98% acid.

Properties of Nitric Acid

Physical Properties

1) Pure nitric acid is a colourless liquid.

2) It has boiling point 355.6 K and freezing point 231.4 K.

3) laboratory grade nitric acid contains about 68% of HNO₃ by mass and has a specific gravity of 1.504.

4) The impure acid is generally yellow due to the presence of nitrogen dioxide as impurity. Nitric acid containing dissolved nitrogen dioxide is known as fuming nitric acid.

5) It has a corrosive action on skin and produces painful blisters.

Chemical Properties

(1) Acidic character: It is one of the strongest acids because it is highly ionised in aqueous solution giving hydronium and nitrate ions.

2HNO₃(aq) +H₂O (l) ——> H₃O⁺ + NO₃¯(aq)

It turns blue litmus red. It forms salts with alkalies, carbonates and bicarbonates.

NaOH + HNO₃ —-> NaNO₃ + H₂O

Na₂CO₃ +  HNO₃ —-> 2NaNO₃ + H₂O + CO₂

NaHCO₃ + HNO₃ —-> NaNO₃ + H₂O + CO₂

(2) Action on metals: With the exception of gold and platinum, nitric acid attacks all metals forming a variety of products. The product depends upon the nature of metal, the concentration of acid and temperature.

(A) Metals that are more electropositive than hydrogen (Mg, Al, Mn, Zn, Fe, Pb, etc.). In this case nascent hydrogen is liberated which further reduces nitric acid.

M + 2HNO₃ ——> M(NO₃)₂ + 2H

HNO₃ + H —-> Reduction product + H₂O

The principal product is NO₂, with conc. HNO₃, N₂O with dil. HNO₃, and ammonium nitrate with very dil. HNO₃.

Uses of Nitric Acid

(i) It is used in the manufacture of ammonium nitrate for fertilizers.

(ii) It is used in the manufacture of sulphuric acid by lead chamber process.

(iii) It is used in the manufacture of explosives such as trinitro toluene (TNT), nitroglycerine, picric acid, etc.

(iv) It is used in the manufacture of dyes, perfumes and silk.

(v) It is used for the manufacture of nitrates for use in explosive and pyrotechnics.

(vi) It is used in picking of stainless steel and etching of metals.

(vii) It is also used as an oxidiser in rocket fuels.

(viii) It is used in the purification of gold and silver as aqua regia.

This is a simulation of the Brownian motion of a big particle (dust particle) that collides with a large set of smaller particles (molecules of a gas) which move with different velocities in different random directions.

Explanation:

Charge of each nucleus = 29e

∴ Net charge 2 gm sphere = (29e) × (2 × 10²²) = 5.8 × 10²³e c.

∴ No of electrons on sphere = 5.8 × 10²³

∴ No of electrons removed to give 2μc charge

= (q/e)

= [(2 × 10^–6)/(1.6 × 10^–19)]

= 1.25 × 10¹³

∴ fraction of electrons removed = [(1.25 × 10¹³)/(5.8 × 10²³)]

= 2.16 × 10^–11

A copper sphere of mass 2 g contains nearly 2 x 10²² atoms. The charge on the nucleus of each atom is 29 e. What fraction of the electrons must be removed from the sphere to give it a charge of +2 μC?

Total number of electrons in the sphere = 29 x 2 x 10²²

the acid is usually manufactured using a method known as the contact process. Earlier, in this process, a chemical element known as platinum was first used as a catalyst. Later, an inorganic compound known as vanadium oxide replaced platinum due to cost constraints.

In any case, today we will be looking at the contact process in detail.

Contact process for manufacturing of sulphuric acid:

Steps involved in the manufacturing of sulphuric acid are as stated below:

1. Preparation of sulphur dioxide.
2. Conversion of sulphur dioxide into sulphur trioxide.
3. Conversion of sulphur trioxide formed into concentrated H₂SO₄.

India's role in Non-Aligned Movement was significant for reasons mentioned below :(i) First Prime Minister of India, Jawaharlal Nehru was one of the five founders of NAM.

(ii) As a leader of NAM, India stayed away from the two camps. Not only this, India asked the newly decolonised countries not to become part Of those alliances.

(iii) It was a policy not of ‘being neutral’ but of active intervention too. India intervened in the Korea war. India tried to involve other members of the non-aligned group with her. India repeatedly tried to activate those regional and international organisations which were not part of the alliances led by the US and USSR.

India was criticised for signing the Treaty of Friendship in August 1971 with the USSR as virtually joining the Soviet alliance system. But in fact India needed diplomatic and possibly military support during the Bangladesh crisis. Moreover, it did not stop India from having good relations with USA and other countries.

Sir:

I am writing this letter to bring your attention to the growing nuisance of auto drivers overcharging in our area. We live in a remote corner from town and the auto drivers always ask for a return fare. I have also noticed that a lot of times the fare from my office to home is different even though the time taken/traffic is almost the same. I need you to raise this concern in your newspaper and also have more traffic inspectors in our area to monitor these auto drivers and have them fined in case they over charge.

thanks you
Yours truly,

a chemical reaction also occurs when ammonia dissolves in water. In aqueous solution, ammonia acts as a base, acquiring hydrogen ions from H₂O to yield ammonium and hydroxide ions. In contrast, the ammonium ion acts as a weak acid in aqueous solution because it dissociates to form hydrogen ion and ammonia.

A substance which increases the speed of a reaction without being consumed in the reaction is called a catalyst. The phenomenon of increasing the rate of reaction by the use of catalyst is called catalysis. Living cells contain thousands of different kinda of proteins called enzymes which act as catalysts.

Urea is a nitrogenous compound formed in the liver. It has a chemical formula of CH4N2O. It is also known as Carbamide or Ureophil. This compound is the final end product of protein metabolism. It is a waste product and has no physiological function. It dissolves in blood and kidney excretes it in urine. This organic compound has two NH2 groups connected by a functional group carbonyl. Urea dissolves in water and is non-toxic. It is colourless and has no smell. It is widely used as an important raw material in industries and commonly used in fertilizers.

• It is used in the manufacture of ammonia, to produce nitric acid and subsequently used as a fertilizer.
• Nitric acid salts include important compounds like potassium nitrate, ammonium nitrate, and nitric acid. Nitrated organic compounds such as nitro glycerine are often explosives.
• Liquid nitrogen is utilized as a refrigerant for transporting foodstuff and freezing purposes. Preservation of bodies and reproductive cells and stable storage of biological samples also makes use of liquid nitrogen.
• Nitrogen makes up 78 percent of the Earth ‘s atmosphere and is a part of all living tissue. Nitrogen is a crucial ingredient of life, since it is a constituent of DNA and as such is part of the genetic code.
• Nitrogen molecules often exist in soil. Nitrogen can be present in nitrates and nitrites in water and in soils. These compounds are all part of the nitrogen cycle and both are interconnected.