Which one of the following process will produce hard water

1. Saturation of water with CaSO4

2. Addition of Na2SO4 to water

3. Saturation of water with CaCO3

4. Saturation of water with MgCO3

Subtopic:  Hard & Soft Water |
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Which of the following statements is incorrect?

1. The equilibrium mixture between ortho and para hydrogen contains 100% of para form at absolute zero

2. In the absence of catalysts, para-hydrogen can be kept for weeks at room temperature in a glass vessel

3. Para form of hydrogen has opposite spins of the two atoms, while ortho form has parallel spins of the two atoms in the hydrogen molecule

4. Para hydrogen is more stable than ortho form and the latter always tends to revert to the stable para form at high temperatures

Subtopic:  Hydrogen- Types & Isotopes |

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Which of the following statements is/are correct for salt like hydrides?

a. Salt like hydrides is formed only by those elements which have very low electronegativity values and can transfer electrons to the hydrogen atom.

b.  Salt like hydrides are solids with ionic lattices.

c.  In fused state they conduct electricity.

d.  The density of salt like hydrides is greater than that of the metal.

 

1.  a, b, c

2.  a, b, c, d

3.  a, b

4.  b, c

Subtopic:  Type of Hydride |
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Half liter each of three samples of H2O2 labeled as 10 vol, 15 vol, and 20 vol are mixed and then each diluted with further half liter of water. The volume strength of resultant H2O2 solution is

1.  5.5

2.  6.5

3.  7.5

4.  8.5

Subtopic:  H2O2 (Hydrogen Peroxide) |

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Excess of Kl and dil H2SO4 were mixed in 50 ml of H2O2. The l2 liberated requires 20 ml of 0.1 N Na2S2O3. The strength of H2O2 is

1.  0.68 g/liter

2.  0.58 g/liter

3.  48 g/liter

4.  38 g/liter

Subtopic:  H2O2 (Hydrogen Peroxide) |

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An ionic compound is dissolved simultaneously in heavy water and ordinary water. Its solubility is

1. Larger in heavy water

2. Smaller in heavy water

3. Solubility is the same in both heavy water as well as ordinary water.

4. Smaller in water

Subtopic:  Water |
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Hydrogen resembles halogens in many respects for which several factors are responsible. Of the following factors which one is most important in this respect?

1.  Its tendency to lose an electron to form a cation.

2.  Its tendency to gain a single electron in its valence shell to attain stable electronic       configuration.

3.  Its low negative electron gain enthalpy value.

4.  Its small size.

Subtopic:  Hydrogen- Types & Isotopes |
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Why does H+ ion always get associated with other atoms or molecules?

1.  Ionization enthalpy of hydrogen resembles that of alkali metals.
2. Its reactivity is similar to halogens.
3.  It resembles both alkali metals and halogens.
4.  Loss of an electron from a hydrogen atom results in a nucleus of very small size as compared to other atoms or ions. Due to small size, it cannot exist free.

Subtopic:  Hydrogen- Types & Isotopes |
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Metal hydrides are ionic, covalent or molecular in nature. Among LiH, NaH, KH, RbH, CsH, the correct order of increasing ionic character is

1.  LiH > NaH > CsH > KH>RbH

2.  LiH < NaH < KH < RbH < CsH

3.  RbH > CsH > NaH > KH > LiH

4.  NaH > CsH > RbH > LiH > KH

Subtopic:  Type of Hydride |
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Which of the following hydrides is electron-precise hydride?

1.  B2H6

2.  NH3

3.  H2O

4.  CH4

Subtopic:  Type of Hydride |
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