I’m not sure, but if I had to guess, it would be that the additional benzene probably lets the mixture be more controllable- the viscosity is just-so, or the ignition properties are specific, etc… versus gasoline, which is a non-standard mixture of hydrocarbons within a certain range.
Lots of 'em, most of which are not appropriate for a public message board. 
I can see it now: The FBI shows up on my doorstep, claiming some dumbass teenager read one of my posts.
Tripler
I do not look good in an orange jumpsuit.
How about the two specific questions in the OP?
< takes notes; @Tripler’s doorstep is not booby trapped. >
The second question has been well addressed: they are most likely styrofoam pellets, probably from a pillow or something.
The first question, re: thick silver liquid: my guess is that it’s lacquer-based or enamel-based paint, which is plenty flammable to make a Molotov cocktail do its thing.
You can see Ukrainians making Molotov’s in great quantities in the short clip at the link below. They are covered in styrofoam (in some parts) from any source they can get their hands on.
Note: This is not a tutorial for making these:
This WW2 training film explains it a little.
To me, the first image looks like the sheen of motor oil mixed with motor fuel. The diesel/gasoline is easier to ignite, but the motor oil burns with a thick, caustic smoke that’s good for choking victims, or marking positions/targets. But this weird silvery sheen makes me also consider it could be an ANFO mixture. My bet, though, is on motor lube & fuel.
The second one, using styrofoam, would coagulate the fuel to make it stickier’n shit. Good for “sliming” napalm that’s tough to put out.
There are other coagulants, that have been mentioned before, but they can get . . . messy.
Tripler
Weird Sheen? Molotov cocktails? What is this, Red Dawn?? Oh. . . wait. . .
Weaponized Beanie Babies…
I hope enough on-point answers have been provided to allow me a tangent.
Lots of photos and videos of abandoned Russian kit have surfaced, often showing the vehicles with their complement of ammunition. If Yuri and his band of resistance fighters get their hands on tank shells and helicopter rockets (sorry, I’m not versed on the correct terminology), to what extent can the ammunition alone be used as a weapon? For instance, can a tank shell be rigged to act as an explosive? The question is just that I’m wondering whether these things have any real value for the Ukrainians.
As I understand it many of the IEDs in Iraq used repurposed standard ordnance warheads and propellants, so it is a possibility.
More on point, a lot of Ukrainian armor, artillery and small arms are Soviet legacy so the rounds for many of these systems are the same on both sides.
Not all tank shells are explosive shells, though. Maybe it would be better to use them as intended (to defeat armour), and to use blocks of plastic explosives as intended if you need a basic demolition charge (similarly, there is “military dynamite” that is just mostly RDX and TNT, industrial explosives, etc, probably not worth dismantling tank rounds unless you want a cool tungsten paperweight).
It’s even more than a lot; pretty much all Ukrainian armor, artillery and small arms are Soviet legacy or modernized Soviet legacy. With some exceptions pretty much any captured ammunition can be used by both sides. One of the major presumed reasons that the Russians were marking all of their vehicles with a white Z, V or triangle was to prevent fratricide since their vehicles if not literally identical are visually indistinguishable from Ukrainian equipment at any distance.
It makes the mixture less flammable so that it’s safer to handle and transport. Modern napalm actually has low flammability and is really hard to ignite. This is overcome by using an igniter based on a hot-burning material like thermite. This way, if a B-52 full of napalm bombs slides off the end of the runway, you’re less likely to lose half your airbase.
You do not need any thermite to ignite even pure benzene. Maybe there is something else about the formulation.
“Molotov cocktails”?
Pfft, who are you old guys? Only geriatric veterans of the Great Patriotic War use those.
The cool kids these days make “Lviv smoothies”.
No, Nazi collaborators are never cool, and by extension anyone who actually identifies with Nazi collaborators.
Yep. But once supplies started dwindling, people switched to more commonoccurence materials. This included using household materials and a little chemistry to manufacture homemade explosives. They’d package the HME in whatever material they wanted, which made it exceedingly dangerous for everyone: “Is that plastic jug just trash, or a deliberately placed item?”
HME chemistry ain’t no joke, either (to do it safely, for good product). It does take some basic wits and supplies. Molotov cocktails? Basic stuff that’s easily trainable, replicatable, and effective.
Tripler
Walter White would have been a great insurgent.
There are videos of slingshot devices being tested to launch said cocktails. Primitive, but a volley at dismounted troops or soft vehicles could be effective.
There are times when you need to drag a kid by the ear to his parents, and then there are times when it’s pretty clear to everyone involved that a lesson has been learned. IME, things involving fire tend to fall into the latter category.