Q1 which hydride doesnt react with water ?
Q2a)NH3
b)PH3
c)B2H6
d)AsH3
Q2 what happens t oacidic strength when OH group is strongly attached to SiO2 derivatives ?
Q3 Compare basicity :(SiH3)3N and (CH3)3N
Q4 general forumula of glass obtained from SIlica is ??
Q5 when two strucutral units of silicates join along a corner containing oxygen atom..then its called ??
19ans 5> orthosilicate
ans 3> trimethyl amine is a much stronger base than trisilyl amine, due to p∩-d∩ dative bond formation in the latter !
ans 4> the repeating unit in glass is R2SiO2-
.....the general formula of glass obtained from silica is R2Si(OH)2
11Ans 1) (b)
Ans 4) essentially SiO2 - Silicon dioxide with added oxides
106Q1. (c) perhaps
Q3. backbonding in N and C (same grp, so overlap is much more effective as orbitals are aprox. same size) iis much more stronger than N and Si (here Si orbitals are much larger so much less effective bonding)
So, lone pair of N exists more on N-Si bond hence N-(SiH3)3 is more basic
24i htink Q3 is becoming confusing ..here are options
a)in (SiH3)3N,LP of Nitrogen is involved in d pi - p pi back bond
b)in (CH3)3N,steric effect of 3 alkyl groups make it leas basic
c)absence of d pi p pi back bond in (CH3)3N
d)all of above
1Q.1) Its c) B2H6 as its in dimer state with all central atoms having complete octet.thus , no vacant orbital for hydrolysis.
Q.3) Lone pair of electrons on N in (SiH3)3N r used up in p pie d- pie back bonding while in (CH3)3N such a p- pie d-pie bonding is not possible due to d absence of vacant d orbitals in carbon .therfore (CH3)3N is more basic than (SiH3)3N .
so, option ' a ' is right.
Q.5) Its pyrosilicates or sorosilicates. they share an O at corners and hv general formula - ( Si2O72-)
1these two, i'm not confirm
Q.2) Perhaps, acidic strength increases. becoz after Si - OH bond is established. H+ goes out as its basic medium , but Si - O bond strength is too strong to be broken. thus, acidic character is enhanced.
Q.4) Its perhaps Si2O52- . xH2O.
1no. ders no p pi-p pi back bonding in (CH3)3N as ders no vacant p - orbital in C in -CH3.
and isn't Q.1) right ? It should be.
rest two, i'm not sure.