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  • 1 answers

Gaurav Seth an hour ago

Hydrogen gas and zinc sulphate are formed when zinc granules are treated with sulphuric acid.

<i>Zn + H2SO4 ⇨ ZnSO4 + H2</i>

Zinc chloride and hydrogen gas are formed, when zinc granules are treated with hydrochloric acid.

<i>Zn + 2HCl ⇨ ZnCl2 + H2</i>

Similarly, hydrogen gas and zinc nitrate are formed when zinc granules are treated with nitric acid.

<i>Zn + 2HNO3 ⇨ Zn(NO3 )2 + H2</i>

Since, zinc is less reactive than sodium, thus no reaction takes place when zinc granules are treated with sodium chloride.

Sodium zincate and hydrogen gas are formed when zinc granules are treated with sodium hydroxide and water.

<i>Zn + 2H2O + 2NaOH ⇨ Na2Zn(OH)4 + H2</i>

  • 5 answers

Saimon Rajpoot 45 minutes ago

Hii koi mujhse dosti karega kya im alone😭

Mahi 😍😍 an hour ago

Khushi are you online

Mahi 😍😍 an hour ago

Can u post now anything now on doubtnut
Are mt btao m smjh gyi...
Aap kiski baat kr rhe ho
  • 1 answers

Gaurav Seth an hour ago

A mixture or an alloy of mercury with a number of metals or alloys such as sodium as well as with some non-metals is known as amalgam.


1. Sodium is highly reactive metal and therefore it is difficult to transport. To lower its reactivity, it is mixed with mercury.

2. Dental amalgam is a mixture of mercury and a silver-tin alloy and is used for fillings in teeth.

Amalgam fillings are often known as “silver fillings.” Dental amalgam is a mixture of mercury, silver, tin and copper. Mercury, which makes up about 50% of the compound, binds the metals together to provide a strong, durable filling.

  • 5 answers

Khushi 💕 40 minutes ago

Go and see in mathematics session...

Saimon Rajpoot 47 minutes ago

Ok send me quotations
Hii gud evening

Khushi 💕 an hour ago

Hiii... Plz tell me ans of my mathematics ques fast...avi
Hii good evening ☀️🙂🙂
  • 1 answers

Gaurav Seth an hour ago


Alloys are homogeneous mixtures of two or more metals or a metal and a non metal.

They are prepared in the following ways:

(i) Melting the primary metal.

(ii) Dissolving the other elements in a definite proportion and then cooling them to room temperature.

Constituents and uses of the alloys are:

1. Brass: It is an alloy of copper and zinc

    Uses: In making utensils and scientific instruments.

2. Bronze: It is an alloy of copper and tin

    Uses: In making statues and medals.

3. Solder: It is an alloy of lead and tin

4. Stainless steel: alloy of Iron

  • 3 answers
Jo aapne pehle send kia h

Khushi 💕 2 hours ago

No problem...🤗🤗
Sry yrr maths wala nhi aata..🙏🙏
  • 4 answers

Saimon Rajpoot 44 minutes ago

Very nice

Yogita Ingle 2 hours ago

The exchange of gases occurs as a result of diffusion down a concentration gradient. Gas molecules move from a region in which they are at high concentration to one in which they are at low concentration. Pulmonary ventilation provides air to the alveoli for this gas exchange process. At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. That is, oxygen moves into the blood by diffusion and combines with the haemoglobin in red blood cells to form oxyhaemoglobin.

Khushi 💕 2 hours ago

Ha ji my dear....❤️❤️
In humans
  • 2 answers

Yogita Ingle 2 hours ago

  1. Pepsin is an enzyme which acts only in acidic medium. Trypsine is an enzyme which acts in alkaline medium.
  2. Pepsin is secreted by gastric juice. Trypsin secreted by pancreatic juice.
  3. Pepsin is secreted in stomach, Trypsin is secreted in small intestine.
  4. Pepsin is situated in gastric glands, Trypsin is situated in pancreas
Pepsin is secretad by gastric galnd whereas trypsin is secreted by pancreas..pepsin secreted in stomach nd trypsin is secreted in small intestine ..
  • 2 answers

Gaurav Seth an hour ago

Wearing a face mask or other covering over the mouth and nose reduces the forward distance traveled by an exhaled breath by more than 90 percent.

 face masks combined with other preventive measures, such as frequent hand-washing and social distancing, help slow the spread of the disease.

Ashwin Gupta 2 hours ago

Face mask make a layer around the face. So face dont have direct contact with other person
  • 1 answers

Gaurav Seth an hour ago

(i) Extraction of copper metal - Copper glance (Cu2S):

1. Concentration of the ore (removal of unwanted metals and gangue to purify the ore) is done by Froth floatation method as it is a sulphide ore.

2. Roasting: Copper glance (Cu2S) is roasted in the presence of air. Roasting turns copper glance (ore of copper) into copper (I) oxide.

3. Reduction: Copper oxide is then heated in the absence of air. This reduces copper (I) oxide into copper metal.

4. Refining impure metal: The reduced metal is purified by electrolytic refining method.

Electrolysis of copper from copper sulphate solution (electrolyte) is done using copper electrodes. The crude copper serves as anode while a thin sheet of pure copper serves as cathode.

The electrolyte consists of an acidic solution of CuSO4. Applying suitable voltage to the electrodes causes, 

oxidation of copper metal at the anode (Cu -----> Cu2+  + 2e) and 

reduction of Cu2+ to form copper metal at the cathode (Cu2+ + 2e -------> Cu).

As the anodes (impure copper) dissolve away, the cathodes on which the pure metal is deposited grow in size.

The impurities in the copper anode which are more active than copper are readily oxidized at the anode but do not plate out at the cathode because their reduction potentials are more negative than that for Cu2+.

  • 2 answers

Yogita Ingle 2 hours ago

Metal carbonates and Metal Hydrogencarbonates reacts with acids and produces corresponding metal salt, carbon dioxide and water.

Let us consider the reaction of sodium carbonate with dilute HCl. The reaction proceeds in the following manner.

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

Vanshika Singh 3 hours ago

They producce CO2 + H20
  • 2 answers
Maine ti aise he pooch liya tha ki aapka name rukhsar h ya nhi
Hlo..yhi pr h
  • 0 answers
  • 1 answers

Avni Jain 5 hours ago

1. Haemodialysis is also known as Artificial kidney. 2.kidney is a very important organ which is essential for maintaining internal homeostatic as it engaged in elimination of the nitrogenous nd other metabolic by -products. 3. Artificial kidney is a physico -chemical device to remove excretory products from blood.
  • 1 answers
a small gland in the skin which secretes a lubricating oily matter (sebum) into the hair follicles to lubricate the skin and hair.
  • 2 answers
Mam how we full the block of these element

Yogita Ingle 6 hours ago

Atomic number of Sodium (Na) – 11
Electronic configuration of Sodium – 1s2 2s2 2p6 3s1
It has one valence electron, it will lose one electron to get octet configuration
Atomic number of Oxygen (O) – 8
Electronic configuration of Oxygen – 1s2 2s2 2p4
It is two electrons short of octet configuration, thus it will gain two electrons.
During the bond formation between Sodium and Oxygen, two Sodium atoms loses one electron each to Oxygen atom.
2 Na -2e-  →  2Na+
O + 2e-     →  O-2
2Na+ + O-2 → Na2O
Atomic number of Magnesium (Mg) – 12
Electronic configuration of Magnesium – 1s2 2s2 2p6 3s2
It has two valence electrons, it will lose two electrons to get octet configuration
Atomic number of Oxygen (O) – 8
Electronic configuration of Oxygen – 1s2 2s2 2p4
It is two electrons short of octet configuration, thus it will gain two electrons.
During the bond formation between Magnesium and Oxygen, one Magnesium atom loses two electrons to Oxygen atom.
Mg -1e-    →  Mg2+
O + 2e-     →  O-2
Mg+2 + O-2 → MgO

  • 2 answers

Gaurav Seth 7 hours ago

They are analogus because they have different structure i.e. humans have complete eye but planaria only have light detcting spots but they perform the same function of seeing

  • 4 answers
Hi shristi

Srishti Gupta 7 hours ago

A spherical mirror is a part of a hollow sphere whose reflecting surface can be made curvee inward or outward by silvering it from the opposite side If you silvered the inward side then the mirror you obtain will be convex whose reflecting surface is facing opposite to the centre of curvature If you silvered the outward side then you will obtain a concave mirror

Gaurav Seth 9 hours ago

  • A spherical mirror, whose reflecting surface is curved inwards, i.e. faces towards the centre of the sphere, is called a concave mirror.

Surya 9 hours ago

There is no sir in this app .Other students answer ur questions
  • 1 answers

Gaurav Seth 9 hours ago

1. They always produce real and inverted images except when an object is placed between the mirror pole and the focus which gives erect virtual images. (for real objects)
2. They produce magnified, diminished and same size images.
3.A parallel beam of incident light is concentrated on its focus and thus such a mirror is called a convergent mirror. Also a light source placed at the focus produces a parallel light beam.
4.Sign convention: The focal length and radius of curvature are taken as negative.

  • 3 answers
Mind your own buisness
Bitch hota hai bhai .

Prateek Maurya 10 hours ago


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