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Multiple choice chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

Ethers are heated with excess of conc. hydrogen halide to give alkyl halide, then the reactivity order of hydrogen halide is :

  1. $HCl < HBr < HF$
  2. $HI > HBr > HCl $
  3. $HF < HCl < HBr $

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When $HX$ is in excess and reaction is carried out at high temperature. Iodine is a good nucleophile, displaces an alcohol molecule by $SN^2$ mechanism thus $HI>HBr>HCl$

Multiple choice chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

Ethyl phenyl ether on boiling with conc. HBr gives: 

  1. phenol and ethane

  2. bromobenzene and ethane

  3. phenol and ethyl bromide

  4. bromobenzene and ethanol
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethyl phenyl ether, an alkyl aryl ether, undergoes cleavage upon heating with concentrated HBr to yield phenol and an alkyl halide. Because the oxygen-phenyl bond has partial double bond character due to resonance, cleavage occurs at the alkyl-oxygen bond, producing phenol and ethyl bromide.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

$MCrO _{4(s)}\overset{CH _{3}COOH(aq)}{\rightarrow}MCrO _{4}$  ( Suspension) above change is correct for which metal ion (s) ? 

  1. $Ba^{2+},Sr^{2+},Ca^{2+}$
  2. $Ba^{2+},Sr^{2+}$
  3. Only $Ba^{2+}$
  4. $Sr^{2+},Ca^{2+}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Barium chromate (BaCrO4) is insoluble in water but dissolves in acidic solutions like acetic acid due to the formation of the dichromate ion. Strontium and calcium chromates are more soluble and do not behave as suspensions in the same way.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

The common name, "cream of tartar" refers to :

  1. $KHC _{4}H _{4}O _{6}$
  2. $K(SbO)C _{4}H _{4}O _{6}$
  3. $KNaC _{4}H _{4}O _{6}$
  4. $Mg _{2} (OH) _{2}(C _{4}H _{4}O _{6})H _{2}O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cream of tartar : Potassium bitartrate(potassium hydrogen tartrate) $KHC _4H _4O _6$

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

$Sr^{2+}$ forms a very unstable complex with $NO _{3-}$. A solution that was $0.001 M - Sr(ClO _{4}) _{2}$ and $0.05 M - KNO _{3}$ was found to have only $75$% of its strontium in the uncomplexed $Sr^{2+}$ form, the balance being $Sr(NO _{3})^{+}$. What is $K _{f}$ for complexation?

  1. $6.67$
  2. $0.15$
  3. $60$
  4. $26.67$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given 25% complexation (0.00025 M) and 75% free Sr2+ (0.00075 M), with [NO3-] = 0.05 M, Kf = [Sr(NO3)+] / ([Sr2+][NO3-]) = 0.00025 / (0.00075 * 0.05) = 0.00025 / 0.0000375 = 6.666...

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

Potash alum is represented by the formula :

  1. $K _2SO _4\cdot Al _2(SO _4) _3\cdot 24H _2O$
  2. $K\cdot Al(SO _4) _2\cdot 12 H _2O$

  3. Both (a) and (b)

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Potassium alum or potassium aluminium sulphate is a chemical compound with a chemical formula $KAl(SO _4) _2$ and it is commonly found in its dodecahydrate form as $KAl(SO _4) _2.12H _2O$. 


Alum is the common name for this chemical compound.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

$KO _2$ (potassium superoxide) is used in oxygen cylinders in space and submarines because, it : 

  1. decomposes to give oxygen

  2. eliminates moisture
  3. absorbs $CO _2$

  4. produces ozone
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

$KO _2$ on decomposition give oxygen and pottassium carbonate.The oxygen is used in oxygen cylinders in space and submarines
$2CO _2+4KO _2\rightarrow 3O _2+2K _2CO _3$.
Hence option A is correct.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

In the reaction : $K _4[Fe(CN) _6] + K _2CO _3\rightarrow $ the product formed is :

  1. $FeCO _3$
  2. $KCN$
  3. $KFeCO _3$
  4. $K _3 [Fe(CN) _6]$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$K _4Fe(CN) _6+K _2CO _3\rightarrow 5KCN+KCNO+Fe+CO _2$.

In the above reaction only KCN is formed.

Hence, option B is correct.