Hydrogen is evolved by the action of cold dilute HNO3 on:
1. Fe
2. Mg or Mn
3. Cu
. Al
A molten ionic hydride on electrolysis gives:
1. H+ ion moving towards the cathode.
2. H+ ion moving towards the anode.
3. H2 is liberated at anode.
4. H2 is liberated at cathode.
Which statement is not correct for hydrogen peroxide?
1. Pure H2O2 is fairly stable
2. It sometimes acts as a reducing agent
3. It acts as an oxidising agent
4. Aqueous solution of H2O2 is weakly basic
In solid hydrogen, the intermolecular bonding is:
1. ionic
2. van der Waals'
3. metallic
4. covalent
The lightest gas is :
1. nitrogen
2. helium
3. oxygen
4. hydrogen
The critical temperature of water is higher than that of O2 because H2O molecule has:
1. fewer electrons than oxygen
2. two covalent bonds
3. V-shape
4. dipole moment
Benzene is oxidized by H2O2 in presence of FeSO4 to:
1. phenol
2. cyclohexane
3. benzaldehyde
4. benzoic acid
The oxidizing property of H2O2 is best explained by assuming that two oxygen atoms in its molecule are:
1. bonded differently
2. bonded similarly
3. bonded covalently
4. bonded by hydrogen bonds
10 volumes of H2O2 has a strength of approximately:
1. 3%
2. 30%
3. 10%
4. 5%
OXIDISINThe incorrect statement among the following regarding H2O2 is -
1. It can only act as an oxidising agent
2. It decomposes on exposure to light
3. It has to be stored in plastic or wax-lined glass bottles in dark
4. It has to be kept away from dust
H2O2 turns an acidified solution of ........ to orange red.
1. BaO2
2. PbO2
3. Na2O2
4. TiO2
Which is not true in case of H2O2?
1. It is more stable in basic solution
2. It acts as strong oxidising agent in acid and basic solutions
3. It is decomposed by MnO2
4. It behaves as reducing agent towards KMnO4
Decmposition of H2O2 is retarded by:
1. acetanilide
2. alcohol
3. H3PO4
4. all of these
The incorrect statement among the following is-
1. Hardness of water depends upon its soap consuming power
2. Temporary hardness is due to bicarbonates of calcium and magnesium
3. Permanent hardness is due to soluble sulphates, chlorides and nitrates of Ca and Mg
4. Permanent hardness can be removed by boiling water
Metal which does not react with cold water but evolves H2 with steam is:
1. Na
2. K
3. Pt
4. Fe
Permutit is:
1. hydrated sodium aluminium silicate
2. sodium hexa meta-phosphate
3. sodium silicate
4. sodium meta-aluminate
Hydrogen is not obtained when zinc reacts with:
1. cold water
2. dil. H2SO4
3. dil HCl
4. hot 20% NaOH
An industrial method of preparation of Hydrogen peroxide is -
1. Action of H2SO4 on barium peroxide
2. Action of H2SO4 on sodium peroxide
3. Auto-oxidation of 2-alkylanthraquinols.
4. Burning hydrogen in excess of oxygen
Ionic hydrides are formed by:
1. Transition metals.
2. Elements of very high electropositivity.
3. Elements of very low electropositivity.
4. Metalloids.
Very pure hydrogen (99.9%) can be made by which of the following processes ?
1. Mixing natural hydrocarbons of high molecular weight
2. Electrolysis of water
3. Reaction of salt like hydrides with water
4. Reaction of methane with steam
Para hydrogen at room temperature is:
1. Less stable than ortho hydrogen.
2. More stable than ortho hydrogen.
3. As stable as ortho hydrogen.
4. None of the above.
Hydrogen combines directly with:
1. Ca
2. Cu
3. Zn
4. Fe
Acidified solution of chromic acid on treatement with H2O2 yields :
1.
2.
3.
4.
The ortho and para hydrogen possess:
1. same physical properties but different chemical properties
2. different physical properties but same chemical properties
3. same chemical and physical properties
4. different physical and chemical properties
On bubbling CO2 through a solution of barium peroxide in water:
1. O2 is formed
2. H2CO3 is formed
3. H2O2 is formed
4. H2 is formed
A mixture of hydrazine and 60 to 90 percent of H2O2 solution is:
1. antiseptic
2. rocket fuel
3. germicide
4. insecticide
A given solution of H2O2 is 30 volume. Its concentration in terms of molarity is:
1. 9.1 M
2. 2.68 M
3. 2.5 M
4. 26.8 M
The decomposition of H2O2 is accelerated by:
1. traces of acids
2. finely divided metals
3. acetanilide
4. alcohol
Hardness of water cannot be removed by -
1. Clark's method
2. Adding washing soda
3. Calgon process
4. Filtration
At pH = X, \(\text{CrO}_4^{2-}\) (yellow) changes to \(\text{Cr}_2\text{O}_7^{2-}\) (orange), and vice versa at pH = Y.
What are the values of X and Y, respectively?
1. 6, and 8
2. 6, and 5
3. 8, and 6
4. 7, and 7
In which reaction hydrogen is not formed ?
(1) Copper and hydrochloric acid
(2) Iron and sulphuric acid
(3) Magnesium and steam
(4) Sodium and alcohol
Which conversion is not done by H2O2 ?
1. (acidic medium)
2.
3. (alkaline medium)
4.
H2O2 restores the colour of old lead paintings by:
1. Converting PbO2 to Pb
2. Oxidising PbS to PbSO4
3. Converting PbCO3 to Pb
4. Oxidizing PbSO3 to PbSO4
(I)
(II)
Role of hydrogen peroxide in the above reactions is respectively
1. oxidising in (I) and reducing in (II)
2. reducing in (I) and oxidising in (II)
3. reducing in (I) and (II)
4. oxidising in(I) and (II)
In acidic medium, H2O2 changes to CrO5 which has two (-O-O-) bonds. Oxidation
state of Cr in CrO5 is
1. +5
2. +3
3. +6
4. -10
Nascent hydrogen consists of
(1) Hydrogen atoms with excess energy
(2) Hydrogen molecules with excess energy
(3) Hydrogen ions in the excited state
(4) Solvated protons
Maximum concentration of ortho- in ordinary hydrogen is:
(1) 75% ortho- + 25% para-
(2) 25% ortho- + 75% para-
(3) 50% ortho- + 50% para-
(4) 99% para- + 1% ortho-
Acidified solution of on treatment with gives
(A)
(B)
(C)
(D)
Blackened oil planting can be restored into original form by the action of:
1. Chlorine
2.
3.
4.
Which of the following statement regarding is wrong.
(1) It is stable in acid medium
(2) It acts as oxidising as well as reducing agent
(3) It has zero dipole moment
(4) Pure is slightly acidic
has higher boiling point than because.
(1) is a smaller molecule and hence more closely packed
(2) The bond angle in is more than in and hence the former molecules are more tightly packed
(3) Of intermolecular hydrogen bonding in liquid
(4) The latent heat of vaporisation is higher for than for
acts as antiseptic due to its –
(1) Reducing property
(2) Oxidising property
(3) Bleaching property
(4) Acidic property
A compound that has both polar and non-polar bonds is –
1.
2.
3.
4.
Exhausted permutit does not contain ............ ion –
(A)
(B)
(C)
(D)
The best explanation for not placing hydrogen with the group of alkali metals or halogens is.
1. Hydrogen can form compounds with all other elements
2. Hydrogen is much lighter element than the alkali metals or the halogens
3. The IE of hydrogen is too high for group of alkali metals but too low for halogen group
4. None of these