Which of these is a base ?

a. vinegar
b. naoh
c. hno3
d. hci

A - Vinegar - Acid

B - NaOH- Base

C - HCL - Acid

D - HNO3 - Acid

NaOH is a base because when it is dissolved in water it dissociates into Na+ and OH- ions. When it had OH- ( hydroxyl ion ) ions, it automaticly is a base; thus, NaOH must be a base.

Hope this helps! :)

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2