107
Q:

Boron cannot form which one of the following anions?

(1) BO2-

(2) BF63-

(3) BH4-

(4) B(OH)4-

A) Option 1 B) Option 2
C) Option 3 D) Option 4

Answer:   B) Option 2



Explanation:

Due to absence of low lying vacant d orbital in B, sp3d2hybridization is not possible hence BF63-will not formed. 

Subject: Chemistry
Exam Prep: AIEEE
Q:

Which one of the following elements cannot be detected by "Lassaigne's test"?

A) I B) Cl
C) S D) F
 
Answer & Explanation Answer: D) F

Explanation:

The sodium fusion test, or Lassaigne's test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens, nitrogen, and sulphur, in an organic compound. It was developed by J. L. Lassaigne.Silver fluoride is soluble in water and does not precipitate and thus this method cannot be used for detection of fluorine.

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Exam Prep: Bank Exams

2 2387
Q:

Match List -I with List -II and select the correct answer using the code given below the Lists :

            List -I                               List-II

(Compound/Molecule)         (Shape of Molecule)

A. CH3F                            1. Trigonal planar

B. HCHO                           2. Tetrahedral

C. HCN                             3. Trigonal pyramidal

D. NH3                             4. Linear

A) 2 4 1 3 B) 2 1 4 3
C) 3 4 1 2 D) 3 1 4 2
 
Answer & Explanation Answer: B) 2 1 4 3

Explanation:

HCHO: The carbon and and the oxygen are bonded through a double bond which counts as "one electron pair". Hence the molecule has three electron pairs and is trigonal planar.

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0 15454
Q:

In case of a standard hydrogen electrode

A) absolute electrode potential is not zero B) absolute electrode potential is zero
C) both absolute and standard electrode potential values are zero D) electrode potential is zero only at 25 deg C
 
Answer & Explanation Answer: A) absolute electrode potential is not zero

Explanation:

The Standard hydrogen electrode (abbreviated SHE), is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Its absolute electrode potential is estimated to be 4.44 ± 0.02 V at 25 °C, but to form a basis for comparison with all other electrode reactions, hydrogen's standard electrode potential (E0) is declared to be zero volts only at 298.

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1 1202
Q:

Which one of the following statements is correct?

A) The oxidation number for hydrogen is always zero. B) The oxidation number for hydrogen is always + 1.
C) The oxidation number for hydrogen is always -1. D) Hydrogen can have more than one oxidation number.
 
Answer & Explanation Answer: D) Hydrogen can have more than one oxidation number.

Explanation:

Hydrogen has two possible oxidation numbers: +1 and -1.

-1 in case of hydrides.

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1 839
Q:

Highest percentage of carbon is found in which form of coal?

A) Anthracite B) Bituminous
C) Peat D) lignite
 
Answer & Explanation Answer: A) Anthracite

Explanation:
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0 972
Q:

Which one of the following elements does not form solid hydrogen carbonate?

A) Sodium B) Potassium
C) Caesium D) Lithium
 
Answer & Explanation Answer: D) Lithium

Explanation:

Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate) is the inorganic compound with the chemical formula KHCO3. It is a white solid

Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder.

LiHCO3 is found in solution form while rest alkali metals hydrogen carbonates are solid due to the anomalous properties of Li and its diagonal relationship with the Mg.

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2 1768
Q:

Bee sting contains________________

A) An acidic liquid B) a salt solution
C) an alkaline liquid D) a corrosive liquid
 
Answer & Explanation Answer: A) An acidic liquid

Explanation:
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Exam Prep: Bank Exams , TOEFL

0 1175
Q:

In paper manufacturing, degumming of the raw material is done using

A) sulphuric acid B) bleaching powder
C) caustic soda D) nitric acid
 
Answer & Explanation Answer: C) caustic soda

Explanation:

Paper production is basically a two-step process in which a fibrous raw material is first converted into pulp, and then the pulp is converted into paper. The harvestedwood is first processed so that the fibres are separated from the unusable fraction of the wood, the lignin. Pulp making can be done mechanically or chemically. In the chemical pulping process, alkali (e.g., sodium hydroxide in the form of a lye or caustic soda) is usually used to remove the lignin that binds the fibres. So, for degumming of raw material, caustic soda is used.

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3 2488