215 - Chemistry Questions Answers

IS BASICITY OF ACETIC ACID IS 1? PLS SEND THE BASICITY OF OTHER ACIDS WHICH ARE USUALLY ASKED  IN ENTRANCE EXAM

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Joshi sir comment

HCl, HNO3 , HCOOH are mono basic acids

COOH-COOH, H2SO4 are di basic acids

similarly others 

 

what is the relation b/w E1 &E2 whose respective wavelength r 400& 800 Ao . SIR I WANT TO KNOW THE RELATn b/w ENERGY & WAVELENGTH . ARE THEY DIRECTLY PROPTIONAL  ? ANS OF THIS QUES IS E1=2E2

Asked By: SARIKA SHARMA
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Joshi sir comment

E = hc/λ

so E is inversely proportional to λ 

THE FIRST EMISSION LINE IN THE ATOMIC SPECTRUM OF HYDROGEN IN BALMER SERIES APPEAR AT ?

ANS 5R/36cm-1

Asked By: SARIKA SHARMA
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Joshi sir comment

for balmer series of hydrogen atom 

 1/λ = R ( 1/22  -   1/32)     

solve for λ

IF n & l are principle & azimuthal quantum no. respectively then expression for calculating total no. of e- in any energy level is?

summation from l=0 to n-1 (2(2l+1)) HOW

Asked By: SARIKA SHARMA
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Joshi sir comment

for nth level values of l will be 0, 1,  2,  3, 4, 5, .....................(n-1) 

for l = 0   means s subshell no. of electrons = 2      = 2(2*0+1) 

for l = 1 means p subshell no. of electrons = 6        = 2(2*1+1)

for l = 2 means d subshell no. of electrons = 10      = 2(2*2+1)

similarly for others 

 

0.2 g OF SAMPLE OF H2O2  REQUIRED 10ml OF 1N KMnO4 SOLn  IN A TITRATION IN +NCE OF dil H2SO4 . THE % PURITY OF H2O2 IS?

ANS 85

 

Asked By: SARIKA SHARMA
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Joshi sir comment

No. of gm. equivalent of KMnO4 = No. of gm. equivalent of H2O2

so 1*10/1000   =     x  /  17             (17 is eq. wt. of H2O2

so  x = 0.17

so % purity = 0.17*100/0.2 = 85 

HOW MUCH WATER IS TO BE ADDED TO DILUTE 10ml OF 10N HCl TO MAKE IT DECINORMAL ?

ANS 100ml

Asked By: SARIKA SHARMA
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Joshi sir comment

N1V1 = N2V2

so 10*10 = 0.1*v 

or v = 1000 ml

so extra water added will be 990 ml

 

the normality of 10% (w/v) acetic acid is ?

1.7N

Asked By: SARIKA SHARMA
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Joshi sir comment

10 % w/v acetic acid means 10 gm. in 100 ml. soln.

so 1000 ml soln. contains 100 gm acetic acid

so 1 litre contains 100/60 moles of acetic acid

so M = 100/60 = 1.67

so N = M * basicity = 1.67*1 = 1.67 

the ques which i have already submitted i.e. d ques in which we have to find min transitional energy in terms ofRH , IS THE ANS IS RH. PLS AGAIN TELL THAT SOLn so that i can understand more easily

Asked By: SARIKA SHARMA
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Joshi sir comment

for max transitional energy we will use 

E = hcRH {1/12  - 1/∞2}

so E will be proportional to RH

oxide of E react with KOH & give compd like KMnO4 WHAT IS THE FORMULA OF OXIDE OF E

EO

E2O3

E2O7      OR ANY OTHER ANS (& IF ANY OTHER ONE THEN GIVE THAT ANS WITH SOLn)

 

Asked By: SARIKA SHARMA
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Joshi sir comment

 

2 EO2 + 4 KOH + O2 → 2 K2EO4 + 2 H2O
and
3 K2EO4 + 2 CO2 → 2 KEO4 + 2 K2CO3 + EO2
 
so oxide will be EO2
 
 
 

IF D POSITn OF Na+ & Cl - rR INTERCHANGED IN NaCl having FCC ARRANGEMENT OF Cl- THEN IN D UNIT CELL OF NaCl

Na + WILL INCREASE  BY 1 WHILE Cl- DECREASE BY 1

PLS TELL D REASON

Asked By: SARIKA
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Joshi sir comment

No, 

These will be no change by making this type of change

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