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Ask QuestionPosted by Sarabjeet Singh 6 years ago
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Atul Sharma 6 years ago
Technology King 6 years ago
Posted by आनंद नागापुरे 6 years ago
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Raunak Chauhan 6 years ago
Yogita Ingle 6 years ago
Silver article become black because silver reacts with H2s gas present in air to form black coating of Ag2S
When the silver react with the hydrogen sulfide gas that is present in the air to form a black coating of silver sulfide. Silver sulfide are insoluble in all the solvents.
The balanced chemical reaction will be,
{tex}2Ag(s)+H_2S(g)\rightarrow Ag_2S(s)+H_2(g){/tex}
By the stoichiometry, 2 moles of silver react with the 1 mole of hydrogen gas to give 1 mole of silver sulfide and 2 moles of hydrogen gas.
Posted by आनंद नागापुरे 6 years ago
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Yogita Ingle 6 years ago
If water has magnesium sulphate dissolved in it for testing it's cleaning action it is to be considered as hard water.
Explanation:
When there is presence of dissolved calcium and magnesium salts in water then this type of water is known as hard water. Hard water leads to the formation of soap lather with difficulty.
On the other hand, soft water contains low concentrations of calcium and magnesium ions. Soft water is capable of forming lather easily when it comes in contact with soap.
Temporary hardness of water is defined as the hardness present due to dissolved calcium hydrogen carbonate which can be removed by boiling the water.
Posted by Arvind Malgi Arvind Malgi 6 years ago
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Yogita Ingle 6 years ago
Centre of curvature of a concave mirror retraces its path (gets reflected along the same path), because as the ray of light passes through centre of curvature of a concave mirror it strikes the mirror along the normal i.e. it incidences on to the mirror at 90 degree. Hence the incident ray coincides with the normal.
Therefore angle of incidence = 0 so, as we know according to law of reflection
angle of reflection = 0, hence the angle of reflection too become zero degree, thus ray of light retraces its path.
Posted by आनंद नागापुरे 6 years ago
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Posted by Arvind Malgi Arvind Malgi 6 years ago
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Posted by Muhammed Gasal.C 6 years ago
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Yogita Ingle 6 years ago
| Homogeneous mixture | Heterogeneous mixture |
| It has a uniform composition | It has a non-uniform composition |
| It has only one phase | There are two or more phases |
| It can’t be separated out physically | It can be separated out physically |
| ‘homo’ means the same | ‘hetero’ means different |
| Example: a mixture of alcohol and water | Example: a mixture of sodium chloride and sand |
Posted by Sirsti Sngm 6 years ago
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Yogita Ingle 6 years ago
Voluntary action:
1. The voluntary actions are under control of Cerebrum (Forebrain).
2. These actions are under the control of will. Examples Reading, Playing
3. These actions are slow when compared to involuntary actions .
4. These actions can control muscles.
Involuntary action:
1. The involuntary actions are under control of Hind brain, Spinal cord.
2. These actions aren't under the control of will. Example Breathing.
3. These actions are rapid.
4. These actions cannot control muscles.
Posted by Saurabh Gupta 6 years ago
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Yogita Ingle 6 years ago
Roasting - In this process, an ore is converted into its oxide by heating it strongly in excess of air. This method is commonly used for sulphide ores. During roasting, moisture and non metallic impurities are also removed as volatile gases .
For example: Zinc sulphide is converted into zinc oxide by roasting.
Tamanna Jaglan 6 years ago
Posted by Lakshay Manchanda 6 years ago
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Yogita Ingle 6 years ago
Formalin is a solution in water of the gas formaldehyde (CH2O). A saturated solution contains about 40% by volume — or 37% by weight — of the gas, plus a small amount of a stabilizer, usually 10-12% methanol; this prevents polymerization.
Posted by Divyansh Singh 6 years ago
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Posted by Tahir Shaikh 6 years ago
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Aadya Singh ? 6 years ago
They are usually liquids or gases .Only some of them are solids.
They have usually Low melting points and low boiling points.
They are usually insoluble in water but they are soluble in organic solvents.
Aadya Singh ? 6 years ago
Ionic compound are usually solid.
It is soluble in water but insoluble in organic solvents.
It conduct electricity when dissolved in water...
Aadya Singh ? 6 years ago
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Posted by Dips ? Tyagi 6 years ago
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Posted by Mujjamil Shaikh 6 years ago
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Yogita Ingle 6 years ago
Let us state Euclid’s division algorithm clearly.
To obtain the HCF of two positive integers, say c and d, with c > d, follow the steps below:
Step 1 : Apply Euclid’s division lemma, to c and d. So, we find whole numbers, q and r such that c = dq + r, 0 ≤ r < d.
Step 2 : If r = 0, d is the HCF of c and d. If r ≠ 0, apply the division lemma to d and r.
Step 3 : Continue the process till the remainder is zero. The divisor at this stage will be the required HCF.
This algorithm works because HCF (c, d) = HCF (d, r) where the symbol HCF (c, d) denotes the HCF of c and d, etc.
Posted by Kartik Kumar 6 years ago
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Gaurav Seth 6 years ago
Cartesian Sign Convention: In the case of spherical mirror all signs are taken from Pole of the spherical mirror, which is often called origin or origin point. This sign convention is known as New Cartesian Sign Convention.
Sign is taken as – (negative) from pole of a spherical mirror towards object along the principal axis. This means sign is always taken as – (negative) in front of a spherical mirror. For example; the distance of object is always taken as – (negative) in case of both types of spherical mirror, i.e. concave and convex mirrors.
- Sign is taken as + (positive) behind the spherical mirror. For example if an image is formed behind the mirror, the distance of image is taken as + (positive) from pole along the principal axis.
- The height of is taken as + (positive) above the principal axis and taken as – (negative) below the principal axis.
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Raunak Chauhan 6 years ago
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